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algorithmbasic2020
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modify code

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左程云 4 years ago
parent 9b66c59d72
commit 10f70fbe68
21 changed files with 219 additions and 225 deletions
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78
src/class18/Code03_Knapsack.java
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package class18;
public class Code03_Knapsack {
public static int getMaxValue(int[] w, int[] v, int bag) {
return process(w, v, 0, 0, bag);
}
// index... 最大价值
public static int process(int[] w, int[] v, int index, int alreadyW, int bag) {
if (alreadyW > bag) {
return -1;
}
// 重量没超
if (index == w.length) {
return 0;
}
int p1 = process(w, v, index + 1, alreadyW, bag);
int p2next = process(w, v, index + 1, alreadyW + w[index], bag);
int p2 = -1;
if (p2next != -1) {
p2 = v[index] + p2next;
}
return Math.max(p1, p2);
}
public static int maxValue(int[] w, int[] v, int bag) {
return process(w, v, 0, bag);
}
// 只剩下rest的空间了，
// index...货物自由选择，但是不要超过rest的空间
// 返回能够获得的最大价值
public static int process(int[] w, int[] v, int index, int rest) {
if (rest < 0) { // base case 1
return -1;
}
// rest >=0
if (index == w.length) { // base case 2
return 0;
}
// 有货也有空间
int p1 = process(w, v, index + 1, rest);
int p2 = -1;
int p2Next = process(w, v, index + 1, rest - w[index]);
if (p2Next != -1) {
p2 = v[index] + p2Next;
}
return Math.max(p1, p2);
}
public static int dpWay(int[] w, int[] v, int bag) {
int N = w.length;
int[][] dp = new int[N + 1][bag + 1];
// dp[N][...] = 0
for (int index = N - 1; index >= 0; index--) {
for (int rest = 0; rest <= bag; rest++) { // rest < 0
int p1 = dp[index + 1][rest];
int p2 = -1;
if (rest - w[index] >= 0) {
p2 = v[index] + dp[index + 1][rest - w[index]];
}
dp[index][rest] = Math.max(p1, p2);
}
}
return dp[0][bag];
}
public static void main(String[] args) {
int[] weights = { 3, 2, 4, 7 };
int[] values = { 5, 6, 3, 19 };
int bag = 11;
System.out.println(maxValue(weights, values, bag));
System.out.println(dpWay(weights, values, bag));
}
}

69
src/class18/Code04_ConvertToLetterString.java
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package class18;
public class Code04_ConvertToLetterString {
public static int number(String str) {
if (str == null || str.length() == 0) {
return 0;
}
return process(str.toCharArray(), 0);
}
public static int process(char[] str, int i) {
if (i == str.length) {
return 1;
}
if (str[i] == '0') {
return 0;
}
if (str[i] == '1') {
int res = process(str, i + 1);
if (i + 1 < str.length) {
res += process(str, i + 2);
}
return res;
}
if (str[i] == '2') {
int res = process(str, i + 1);
if (i + 1 < str.length && (str[i + 1] >= '0' && str[i + 1] <= '6')) {
res += process(str, i + 2); // (i和i+1)作为单独的部分，后续有多少种方法
}
return res;
}
return process(str, i + 1);
}
public static int dp(String s) {
if (s == null || s.length() == 0) {
return 0;
}
char[] str = s.toCharArray();
int N = str.length;
int[] dp = new int[N + 1];
dp[N] = 1;
for (int i = N - 1; i >= 0; i--) {
if (str[i] == '0') {
dp[i] = 0;
} else if (str[i] == '1') {
dp[i] = dp[i + 1];
if (i + 1 < N) {
dp[i] += dp[i + 2];
}
} else if (str[i] == '2') {
dp[i] = dp[i + 1];
if (i + 1 < str.length && (str[i + 1] >= '0' && str[i + 1] <= '6')) {
dp[i] += dp[i + 2];
}
} else {
dp[i] = dp[i + 1];
}
}
return dp[0];
}
public static void main(String[] args) {
System.out.println(number("2132082"));
System.out.println(dp("2132082"));
}
}

63
src/class19/Code01_Knapsack.java
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@ -0,0 +1,63 @@
package class19;
public class Code01_Knapsack {
// 所有的货，重量和价值，都在w和v数组里
// 为了方便，其中没有负数
// bag背包容量，不能超过这个载重
// 返回：不超重的情况下，能够得到的最大价值
public static int maxValue(int[] w, int[] v, int bag) {
if (w == null || v == null || w.length != v.length || w.length == 0) {
return 0;
}
// 尝试函数！
return process(w, v, 0, bag);
}
// index 0~N
// rest 负~bag
public static int process(int[] w, int[] v, int index, int rest) {
if (rest < 0) {
return -1;
}
if (index == w.length) {
return 0;
}
int p1 = process(w, v, index + 1, rest);
int p2 = 0;
int next = process(w, v, index + 1, rest - w[index]);
if (next != -1) {
p2 = v[index] + next;
}
return Math.max(p1, p2);
}
public static int dp(int[] w, int[] v, int bag) {
if (w == null || v == null || w.length != v.length || w.length == 0) {
return 0;
}
int N = w.length;
int[][] dp = new int[N + 1][bag + 1];
for (int index = N - 1; index >= 0; index--) {
for (int rest = 0; rest <= bag; rest++) {
int p1 = dp[index + 1][rest];
int p2 = 0;
int next = rest - w[index] < 0 ? -1 : dp[index + 1][rest - w[index]];
if (next != -1) {
p2 = v[index] + next;
}
dp[index][rest] = Math.max(p1, p2);
}
}
return dp[0][bag];
}
public static void main(String[] args) {
int[] weights = { 3, 2, 4, 7, 3, 1, 7 };
int[] values = { 5, 6, 3, 19, 12, 4, 2 };
int bag = 15;
System.out.println(maxValue(weights, values, bag));
System.out.println(dp(weights, values, bag));
}
}

58
src/class19/Code01_LongestCommonSubsequence.java
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@ -1,58 +0,0 @@
package class19;
// 这个问题leetcode上可以直接测
// 链接：https://leetcode.com/problems/longest-common-subsequence/
public class Code01_LongestCommonSubsequence {
public static int longestCommonSubsequence1(String text1, String text2) {
if (text1 == null || text2 == null || text1.length() == 0 || text2.length() == 0) {
return 0;
}
return process(text1.toCharArray(), text2.toCharArray(), text1.length() - 1, text2.length() - 1);
}
// str1[0..i]与str2[0..j]最长公共子序列多长
public static int process(char[] str1, char[] str2, int i, int j) {
if (i == 0 && j == 0) {
return str1[0] == str2[0] ? 1 : 0;
}
if (i == 0) {
return str1[0] == str2[j] ? 1 : process(str1, str2, 0, j - 1);
}
if (j == 0) {
return str1[i] == str2[0] ? 1 : process(str1, str2, i - 1, 0);
}
int p1 = process(str1, str2, i - 1, j);
int p2 = process(str1, str2, i, j - 1);
int p3 = str1[i] == str2[j] ? (process(str1, str2, i - 1, j - 1) + 1) : 0;
return Math.max(Math.max(p1, p2), p3);
}
public static int longestCommonSubsequence2(String text1, String text2) {
if (text1 == null || text2 == null || text1.length() == 0 || text2.length() == 0) {
return 0;
}
char[] str1 = text1.toCharArray();
char[] str2 = text2.toCharArray();
int N = str1.length;
int M = str2.length;
int[][] dp = new int[N][M];
dp[0][0] = str1[0] == str2[0] ? 1 : 0;
for (int i = 1; i < N; i++) {
dp[i][0] = str1[i] == str2[0] ? 1 : dp[i - 1][0];
}
for (int j = 1; j < M; j++) {
dp[0][j] = str1[0] == str2[j] ? 1 : dp[0][j - 1];
}
for (int i = 1; i < N; i++) {
for (int j = 1; j < M; j++) {
dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
if (str1[i] == str2[j]) {
dp[i][j] = Math.max(dp[i][j], dp[i - 1][j - 1] + 1);
}
}
}
return dp[N - 1][M - 1];
}
}

58
src/class19/Code02_ConvertToLetterString.java
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package class19;
public class Code02_ConvertToLetterString {
// str只含有数字字符0~9
// 返回多少种转化方案
public static int number(String str) {
if (str == null || str.length() == 0) {
return 0;
}
return process(str.toCharArray(), 0);
}
// str[0..i-1]转化无需过问
// str[i.....]去转化，返回有多少种转化方法
public static int process(char[] str, int i) {
if (i == str.length) {
return 1;
}
// i没到最后，说明有字符
if (str[i] == '0') { // 之前的决定有问题
return 0;
}
// str[i] != '0'
// 可能性一，i单转
int ways = process(str, i + 1);
if (i + 1 < str.length && (str[i] - '0') * 10 + str[i + 1] - '0' < 27) {
ways += process(str, i + 2);
}
return ways;
}
public static int dp(String s) {
if (s == null || s.length() == 0) {
return 0;
}
char[] str = s.toCharArray();
int N = str.length;
int[] dp = new int[N + 1];
dp[N] = 1;
for (int i = N - 1; i >= 0; i--) {
if (str[i] != '0') {
int ways = dp[i + 1];
if (i + 1 < str.length && (str[i] - '0') * 10 + str[i + 1] - '0' < 27) {
ways += dp[i + 2];
}
dp[i] = ways;
}
}
return dp[0];
}
public static void main(String[] args) {
System.out.println(number("7210231231232031203123"));
System.out.println(dp("7210231231232031203123"));
}
}

15
src/class18/Code05_StickersToSpellWord.java → src/class19/Code03_StickersToSpellWord.java
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@ -1,15 +1,18 @@
package class18;
package class19;
import java.util.HashMap;
// 本题测试链接：https://leetcode.com/problems/stickers-to-spell-word
public class Code05_StickersToSpellWord {
public class Code03_StickersToSpellWord {
public static int minStickers1(String[] stickers, String target) {
int ans = process1(stickers, target);
return ans == Integer.MAX_VALUE ? -1 : ans;
}
// 所有贴纸stickers，每一种贴纸都有无穷张
// target
// 最少张数
public static int process1(String[] stickers, String target) {
if (target.length() == 0) {
return 0;
@ -59,10 +62,17 @@ public class Code05_StickersToSpellWord {
return ans == Integer.MAX_VALUE ? -1 : ans;
}
// stickers[i] 数组，当初i号贴纸的字符统计 int[][] stickers -> 所有的贴纸
// 每一种贴纸都有无穷张
// 返回搞定target的最少张数
// 最少张数
public static int process2(int[][] stickers, String t) {
if (t.length() == 0) {
return 0;
}
// target做出词频统计
// target aabbc 2 2 1..
// 0 1 2..
char[] target = t.toCharArray();
int[] tcounts = new int[26];
for (char cha : target) {
@ -71,6 +81,7 @@ public class Code05_StickersToSpellWord {
int N = stickers.length;
int min = Integer.MAX_VALUE;
for (int i = 0; i < N; i++) {
// 尝试第一张贴纸是谁
int[] sticker = stickers[i];
// 最关键的优化(重要的剪枝!这一步也是贪心!)
if (sticker[target[0] - 'a'] > 0) {

67
src/class19/Code04_LongestCommonSubsequence.java
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@ -0,0 +1,67 @@
package class19;
// 这个问题leetcode上可以直接测
// 链接：https://leetcode.com/problems/longest-common-subsequence/
public class Code04_LongestCommonSubsequence {
public static int longestCommonSubsequence1(String s1, String s2) {
if (s1 == null || s2 == null || s1.length() == 0 || s2.length() == 0) {
return 0;
}
char[] str1 = s1.toCharArray();
char[] str2 = s2.toCharArray();
// 尝试
return process1(str1, str2, str1.length - 1, str2.length - 1);
}
public static int process1(char[] str1, char[] str2, int i, int j) {
if (i == 0 && j == 0) {
return str1[i] == str2[j] ? 1 : 0;
} else if (i == 0) {
if (str1[i] == str2[j]) {
return 1;
} else {
return process1(str1, str2, i, j - 1);
}
} else if (j == 0) {
if (str1[i] == str2[j]) {
return 1;
} else {
return process1(str1, str2, i - 1, j);
}
} else { // i != 0 && j != 0
int p1 = process1(str1, str2, i - 1, j);
int p2 = process1(str1, str2, i, j - 1);
int p3 = str1[i] == str2[j] ? (1 + process1(str1, str2, i - 1, j - 1)) : 0;
return Math.max(p1, Math.max(p2, p3));
}
}
public static int longestCommonSubsequence2(String s1, String s2) {
if (s1 == null || s2 == null || s1.length() == 0 || s2.length() == 0) {
return 0;
}
char[] str1 = s1.toCharArray();
char[] str2 = s2.toCharArray();
int N = str1.length;
int M = str2.length;
int[][] dp = new int[N][M];
dp[0][0] = str1[0] == str2[0] ? 1 : 0;
for (int j = 1; j < M; j++) {
dp[0][j] = str1[0] == str2[j] ? 1 : dp[0][j - 1];
}
for (int i = 1; i < N; i++) {
dp[i][0] = str1[i] == str2[0] ? 1 : dp[i - 1][0];
}
for (int i = 1; i < N; i++) {
for (int j = 1; j < M; j++) {
int p1 = dp[i - 1][j];
int p2 = dp[i][j - 1];
int p3 = str1[i] == str2[j] ? (1 + dp[i - 1][j - 1]) : 0;
dp[i][j] = Math.max(p1, Math.max(p2, p3));
}
}
return dp[N - 1][M - 1];
}
}

4
src/class19/Code02_PalindromeSubsequence.java → src/class20/Code01_PalindromeSubsequence.java
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@ -1,7 +1,7 @@
package class19;
package class20;
// 测试链接：https://leetcode.com/problems/longest-palindromic-subsequence/
public class Code02_PalindromeSubsequence {
public class Code01_PalindromeSubsequence {
public static int longestPalindromeSubseq1(String s) {
if (s == null || s.length() == 0) {

4
src/class19/Code03_HorseJump.java → src/class20/Code02_HorseJump.java
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@ -1,6 +1,6 @@
package class19;
package class20;
public class Code03_HorseJump {
public class Code02_HorseJump {
public static int ways(int a, int b, int step) {
return f(0, 0, step, a, b);

4
src/class19/Code04_Coffee.java → src/class20/Code03_Coffee.java
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@ -1,4 +1,4 @@
package class19;
package class20;
import java.util.Arrays;
import java.util.Comparator;
@ -12,7 +12,7 @@ import java.util.PriorityQueue;
// 洗杯子的机器洗完一个杯子时间为a，任何一个杯子自然挥发干净的时间为b。
// 四个参数：arr, n, a, b
// 假设时间点从0开始，返回所有人喝完咖啡并洗完咖啡杯的全部过程结束后，至少来到什么时间点。
public class Code04_Coffee {
public class Code03_Coffee {
// 方法一：暴力尝试方法
public static int minTime1(int[] arr, int n, int a, int b) {

4
src/class19/Code05_MinPathSum.java → src/class20/Code04_MinPathSum.java
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@ -1,6 +1,6 @@
package class19;
package class20;
public class Code05_MinPathSum {
public class Code04_MinPathSum {
public static int minPathSum1(int[][] m) {
if (m == null || m.length == 0 || m[0] == null || m[0].length == 0) {

2
src/class20/Code01_CoinsWayEveryPaperDifferent.java → src/class21/Code01_CoinsWayEveryPaperDifferent.java
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@ -1,4 +1,4 @@
package class20;
package class21;
public class Code01_CoinsWayEveryPaperDifferent {

2
src/class20/Code02_CoinsWayNoLimit.java → src/class21/Code02_CoinsWayNoLimit.java
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@ -1,4 +1,4 @@
package class20;
package class21;
public class Code02_CoinsWayNoLimit {

2
src/class20/Code03_CoinsWaySameValueSamePapper.java → src/class21/Code03_CoinsWaySameValueSamePapper.java
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@ -1,4 +1,4 @@
package class20;
package class21;
import java.util.HashMap;
import java.util.Map.Entry;

2
src/class20/Code04_MinCoinsOnePaper.java → src/class21/Code04_MinCoinsOnePaper.java
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@ -1,4 +1,4 @@
package class20;
package class21;
import java.util.HashMap;
import java.util.Map.Entry;

2
src/class20/Code05_MinCoinsNoLimit.java → src/class21/Code05_MinCoinsNoLimit.java
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@ -1,4 +1,4 @@
package class20;
package class21;
public class Code05_MinCoinsNoLimit {

2
src/class21/Code01_BobDie.java → src/class22/Code01_BobDie.java
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@ -1,4 +1,4 @@
package class21;
package class22;
public class Code01_BobDie {

2
src/class21/Code02_KillMonster.java → src/class22/Code02_KillMonster.java
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@ -1,4 +1,4 @@
package class21;
package class22;
public class Code02_KillMonster {

2
src/class21/Code03_SplitSumClosed.java → src/class22/Code03_SplitSumClosed.java
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@ -1,4 +1,4 @@
package class21;
package class22;
import java.util.TreeSet;

2
src/class21/Code04_SplitSumClosedSizeHalf.java → src/class22/Code04_SplitSumClosedSizeHalf.java
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@ -1,4 +1,4 @@
package class21;
package class22;
import java.util.TreeSet;

2
src/class21/Code05_NQueens.java → src/class22/Code05_NQueens.java
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@ -1,4 +1,4 @@
package class21;
package class22;
public class Code05_NQueens {
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