From b8b42156efcf175b258bc87d5d199c0385b2e1a8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=B7=A6=E7=A8=8B=E4=BA=91?= Date: Thu, 18 Mar 2021 14:18:56 +0800 Subject: [PATCH] modify code --- src/class39/Code01_SubsquenceMaxModM.java | 15 ++- src/class39/Code02_SnacksWaysMain.java | 44 +++++++ src/class41/Code02_StoneMerge.java | 114 ++++++++++++++++++ ....java => Code03_SplitArrayLargestSum.java} | 2 +- 4 files changed, 166 insertions(+), 9 deletions(-) create mode 100644 src/class41/Code02_StoneMerge.java rename src/class41/{Code02_SplitArrayLargestSum.java => Code03_SplitArrayLargestSum.java} (98%) diff --git a/src/class39/Code01_SubsquenceMaxModM.java b/src/class39/Code01_SubsquenceMaxModM.java index 5014e4b..9890bf4 100644 --- a/src/class39/Code01_SubsquenceMaxModM.java +++ b/src/class39/Code01_SubsquenceMaxModM.java @@ -40,7 +40,7 @@ public class Code01_SubsquenceMaxModM { for (int j = 1; j <= sum; j++) { dp[i][j] = dp[i - 1][j]; if (j - arr[i] >= 0) { - dp[i][j] = dp[i][j] | dp[i - 1][j - arr[i]]; + dp[i][j] |= dp[i - 1][j - arr[i]]; } } } @@ -51,11 +51,11 @@ public class Code01_SubsquenceMaxModM { } } return ans; - } public static int max3(int[] arr, int m) { int N = arr.length; + // 0...m-1 boolean[][] dp = new boolean[N][m]; for (int i = 0; i < N; i++) { dp[i][0] = true; @@ -66,11 +66,10 @@ public class Code01_SubsquenceMaxModM { // dp[i][j] T or F dp[i][j] = dp[i - 1][j]; int cur = arr[i] % m; - if (j - cur >= 0) { - dp[i][j] = dp[i][j] | dp[i - 1][j - cur]; - } - if (j - cur < 0) { - dp[i][j] = dp[i][j] | dp[i - 1][m + j - cur]; + if (cur <= j) { + dp[i][j] |= dp[i - 1][j - cur]; + } else { + dp[i][j] |= dp[i - 1][m + j - cur]; } } } @@ -132,7 +131,7 @@ public class Code01_SubsquenceMaxModM { int ans3 = max3(arr, m); int ans4 = max4(arr, m); if (ans1 != ans2 || ans2 != ans3 || ans3 != ans4) { - System.out.print("Oops!"); + System.out.println("Oops!"); } } System.out.println("test finish!"); diff --git a/src/class39/Code02_SnacksWaysMain.java b/src/class39/Code02_SnacksWaysMain.java index 574b409..a224dc7 100644 --- a/src/class39/Code02_SnacksWaysMain.java +++ b/src/class39/Code02_SnacksWaysMain.java @@ -56,6 +56,50 @@ public class Code02_SnacksWaysMain { return ways + 1; } + + + + // arr 30 + // func(arr, 0, 14, 0, bag, map) + + // func(arr, 15, 29, 0, bag, map) + + // 从index出发，到end结束 + // 之前的选择，已经形成的累加和sum + // 零食[index....end]自由选择，出来的所有累加和，不能超过bag，每一种累加和对应的方法数，填在map里 + // 最后不能什么货都没选 + // [3,3,3,3] bag = 6 + // 0 1 2 3 + // - - - - 0 -> （0 : 1） + // - - - $ 3 -> （0 : 1）(3, 1) + // - - $ - 3 -> （0 : 1）(3, 2) + public static long func(int[] arr, int index, int end, long sum, long bag, TreeMap map) { + if(sum > bag) { + return 0; + } + // sum <= bag + if(index > end) { // 所有商品自由选择完了！ + // sum + if(sum != 0) { + if (!map.containsKey(sum)) { + map.put(sum, 1L); + } else { + map.put(sum, map.get(sum) + 1); + } + return 1; + } else { + return 0; + } + } + // sum <= bag 并且 index <= end(还有货) + // 1) 不要当前index位置的货 + long ways = func(arr, index + 1, end, sum, bag, map); + + // 2) 要当前index位置的货 + ways += func(arr, index + 1, end, sum + arr[index], bag, map); + return ways; + } + public static long process(int[] arr, int index, long w, int end, int bag, TreeMap map) { if (w > bag) { return 0; diff --git a/src/class41/Code02_StoneMerge.java b/src/class41/Code02_StoneMerge.java new file mode 100644 index 0000000..3b3d7ae --- /dev/null +++ b/src/class41/Code02_StoneMerge.java @@ -0,0 +1,114 @@ +package class41; + +public class Code02_StoneMerge { + + public static int[] sum(int[] arr) { + int N = arr.length; + int[] s = new int[N + 1]; + s[0] = 0; + for (int i = 0; i < N; i++) { + s[i + 1] = s[i] + arr[i]; + } + return s; + } + + public static int w(int[] s, int l, int r) { + return s[r + 1] - s[l]; + } + + public static int min1(int[] arr) { + if (arr == null || arr.length < 2) { + return 0; + } + int N = arr.length; + int[] s = sum(arr); + return process1(0, N - 1, s); + } + + public static int process1(int L, int R, int[] s) { + if (L == R) { + return 0; + } + int next = Integer.MAX_VALUE; + for (int leftEnd = L; leftEnd < R; leftEnd++) { + next = Math.min(next, process1(L, leftEnd, s) + process1(leftEnd + 1, R, s)); + } + return next + w(s, L, R); + } + + public static int min2(int[] arr) { + if (arr == null || arr.length < 2) { + return 0; + } + int N = arr.length; + int[] s = sum(arr); + int[][] dp = new int[N][N]; + for (int L = N - 2; L >= 0; L--) { + for (int R = L + 1; R < N; R++) { + int next = Integer.MAX_VALUE; + for (int leftEnd = L; leftEnd < R; leftEnd++) { + next = Math.min(next, dp[L][leftEnd] + dp[leftEnd + 1][R]); + } + dp[L][R] = next + w(s, L, R); + } + } + return dp[0][N - 1]; + } + + public static int min3(int[] arr) { + if (arr == null || arr.length < 2) { + return 0; + } + int N = arr.length; + int[] s = sum(arr); + int[][] dp = new int[N][N]; + int[][] best = new int[N][N]; + for (int i = 0; i < N - 1; i++) { + best[i][i + 1] = i; + dp[i][i + 1] = w(s, i, i + 1); + } + for (int L = N - 3; L >= 0; L--) { + for (int R = L + 2; R < N; R++) { + int next = Integer.MAX_VALUE; + int choose = -1; + for (int leftEnd = best[L][R - 1]; leftEnd <= best[L + 1][R]; leftEnd++) { + int cur = dp[L][leftEnd] + dp[leftEnd + 1][R]; + if (cur < next) { + next = cur; + choose = leftEnd; + } + } + best[L][R] = choose; + dp[L][R] = next + w(s, L, R); + } + } + return dp[0][N - 1]; + } + + public static int[] randomArray(int len, int maxValue) { + int[] arr = new int[len]; + for (int i = 0; i < len; i++) { + arr[i] = (int) (Math.random() * maxValue); + } + return arr; + } + + public static void main(String[] args) { + int N = 15; + int maxValue = 100; + int testTime = 1000; + System.out.println("test begin"); + for (int i = 0; i < testTime; i++) { + int len = (int) (Math.random() * N); + int[] arr = randomArray(len, maxValue); + int ans1 = min1(arr); + int ans2 = min2(arr); + int ans3 = min3(arr); + if (ans1 != ans2 || ans1 != ans3) { + System.out.println("Oops!"); + } + } + System.out.println("test end"); + } + +} diff --git a/src/class41/Code02_SplitArrayLargestSum.java b/src/class41/Code03_SplitArrayLargestSum.java similarity index 98% rename from src/class41/Code02_SplitArrayLargestSum.java rename to src/class41/Code03_SplitArrayLargestSum.java index 0de1cea..c83922d 100644 --- a/src/class41/Code02_SplitArrayLargestSum.java +++ b/src/class41/Code03_SplitArrayLargestSum.java @@ -1,6 +1,6 @@ package class41; -public class Code02_SplitArrayLargestSum { +public class Code03_SplitArrayLargestSum { public static int splitArray1(int[] nums, int m) { return process(nums, 0, m);