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algorithmbasic2020
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modify code

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pull/6/head
左程云 5 years ago
parent 78e5dc4d7c
commit 0106bd9d69
2 changed files with 92 additions and 75 deletions
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55
src/class24/Code01_SlidingWindowMaxArray.java
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@ -4,28 +4,43 @@ import java.util.LinkedList;
public class Code01_SlidingWindowMaxArray {
// 暴力的对数器方法
public static int[] right(int[] arr, int w) {
if (arr == null || w < 1 || arr.length < w) {
return null;
}
int[] res = new int[arr.length - w + 1];
int index = 0;
int L = 0;
int R = w - 1;
while (R < arr.length) {
int max = arr[L];
for (int i = L + 1; i <= R; i++) {
max = Math.max(max, arr[i]);
}
res[index++] = max;
L++;
R++;
}
return res;
}
public static int[] getMaxWindow(int[] arr, int w) {
if (arr == null || w < 1 || arr.length < w) {
return null;
}
// 其中放的是位置，头代表 （大->小）尾
LinkedList<Integer> qmax = new LinkedList<Integer>();
int[] res = new int[arr.length - w + 1];
int index = 0;
// L...R
// i
for (int R = 0; R < arr.length; R++) { // 当前让 i -> [i] 进窗口 ， i 就是 r
// R -> 值 可以放在比他大的数后，或者空
for (int R = 0; R < arr.length; R++) {
while (!qmax.isEmpty() && arr[qmax.peekLast()] <= arr[R]) {
qmax.pollLast();
}
qmax.addLast(R);
// 数进来了
// 如果窗口没有形成W的长度之前，不弹出数字的
if (qmax.peekFirst() == R - w) {
qmax.pollFirst();
}
// 以上窗口更新做完了
if (R >= w - 1) {
res[index++] = arr[qmax.peekFirst()];
}
@ -33,28 +48,6 @@ public class Code01_SlidingWindowMaxArray {
return res;
}
// for test
public static int[] rightWay(int[] arr, int w) {
if (arr == null || w < 1 || arr.length < w) {
return null;
}
int[] res = new int[arr.length - w + 1];
int index = 0;
int L = 0;
int R = w - 1;
while (R < arr.length) {
int max = arr[L];
for (int i = L + 1; i <= R; i++) {
max = Math.max(max, arr[i]);
}
res[index++] = max;
L++;
R++;
}
return res;
}
// for test
public static int[] generateRandomArray(int maxSize, int maxValue) {
int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
@ -92,7 +85,7 @@ public class Code01_SlidingWindowMaxArray {
int[] arr = generateRandomArray(maxSize, maxValue);
int w = (int) (Math.random() * (arr.length + 1));
int[] ans1 = getMaxWindow(arr, w);
int[] ans2 = rightWay(arr, w);
int[] ans2 = right(arr, w);
if (!isEqual(ans1, ans2)) {
System.out.println("Oops!");
}

112
src/class24/Code02_AllLessNumSubArray.java
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@ -4,62 +4,71 @@ import java.util.LinkedList;
public class Code02_AllLessNumSubArray {
public static int getNum(int[] arr, int num) {
if (arr == null || arr.length == 0) {
// 暴力的对数器方法
public static int right(int[] arr, int sum) {
if (arr == null || arr.length == 0 || sum < 0) {
return 0;
}
LinkedList<Integer> qmin = new LinkedList<Integer>();
LinkedList<Integer> qmax = new LinkedList<Integer>();
int L = 0;
int R = 0;
// [L..R) -> [0,0) 窗口内无数 [1,1)
// [0,1) -> [0~0]
int res = 0;
while (L < arr.length) { // L是开头位置，尝试每一个开头
// 如果此时窗口的开头是L,下面的while工作:R向右扩到违规为止
while (R < arr.length) { // R是最后一个达标位置的再下一个
while (!qmin.isEmpty() && arr[qmin.peekLast()] >= arr[R]) {
qmin.pollLast();
int N = arr.length;
int count = 0;
for (int L = 0; L < N; L++) {
for (int R = L; R < N; R++) {
int max = arr[L];
int min = arr[L];
for (int i = L + 1; i <= R; i++) {
max = Math.max(max, arr[i]);
min = Math.min(min, arr[i]);
}
qmin.addLast(R);
// R -> arr[R],
while (!qmax.isEmpty() && arr[qmax.peekLast()] <= arr[R]) {
qmax.pollLast();
if (max - min <= sum) {
count++;
}
qmax.addLast(R);
}
}
return count;
}
if (arr[qmax.getFirst()] - arr[qmin.getFirst()] > num) {
public static int num(int[] arr, int sum) {
if (arr == null || arr.length == 0 || sum < 0) {
return 0;
}
int N = arr.length;
int count = 0;
LinkedList<Integer> maxWindow = new LinkedList<>();
LinkedList<Integer> minWindow = new LinkedList<>();
int R = 0;
for (int L = 0; L < N; L++) {
while (R < N) {
while (!maxWindow.isEmpty() && arr[maxWindow.peekLast()] <= arr[R]) {
maxWindow.pollLast();
}
maxWindow.addLast(R);
while (!minWindow.isEmpty() && arr[minWindow.peekLast()] >= arr[R]) {
minWindow.pollLast();
}
minWindow.addLast(R);
if (arr[maxWindow.peekFirst()] - arr[minWindow.peekFirst()] > sum) {
break;
} else {
R++;
}
R++;
}
// R是最后一个达标位置的再下一个，第一个违规的位置
res += R - L;
if (qmin.peekFirst() == L) {
qmin.pollFirst();
count += R - L;
if (maxWindow.peekFirst() == L) {
maxWindow.pollFirst();
}
if (qmax.peekFirst() == L) {
qmax.pollFirst();
if (minWindow.peekFirst() == L) {
minWindow.pollFirst();
}
L++;
}
return res;
return count;
}
// for test
public static int[] getRandomArray(int len) {
if (len < 0) {
return null;
}
public static int[] generateRandomArray(int maxLen, int maxValue) {
int len = (int) (Math.random() * (maxLen + 1));
int[] arr = new int[len];
for (int i = 0; i < len; i++) {
arr[i] = (int) (Math.random() * 10);
arr[i] = (int) (Math.random() * (maxValue + 1)) - (int) (Math.random() * (maxValue + 1));
}
return arr;
}
@ -75,10 +84,25 @@ public class Code02_AllLessNumSubArray {
}
public static void main(String[] args) {
int[] arr = getRandomArray(30);
int num = 5;
printArray(arr);
System.out.println(getNum(arr, num));
int maxLen = 100;
int maxValue = 200;
int testTime = 100000;
System.out.println("测试开始");
for (int i = 0; i < testTime; i++) {
int[] arr = generateRandomArray(maxLen, maxValue);
int sum = (int) (Math.random() * (maxValue + 1));
int ans1 = right(arr, sum);
int ans2 = num(arr, sum);
if (ans1 != ans2) {
System.out.println("Oops!");
printArray(arr);
System.out.println(sum);
System.out.println(ans1);
System.out.println(ans2);
break;
}
}
System.out.println("测试结束");
}

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