代码随想录-动态规划Part11

1143.最长公共子序列

class Solution { public int longestCommonSubsequence(String text1, String text2) { int n1 = text1.length(); int n2 = text2.length(); int [] dp = new int[n2 + 1]; for(int i = 1; i <= n1; i++){ int pre = dp[0]; for(int j = 1; j <= n2; j++){ int cur = dp[j]; if(text1.charAt(i - 1) == text2.charAt(j - 1)){ dp[j] = pre + 1; } else{ dp[j] = Math.max(dp[j], dp[j - 1]); } pre = cur; } } return dp[n2]; } }

1035.不相交的线

class Solution { public int maxUncrossedLines(int[] nums1, int[] nums2) { int len1 = nums1.length; int len2 = nums2.length; int[][] dp = new int[len1 + 1][len2 + 1]; for (int i = 1; i <= len1; i++) { for (int j = 1; j <= len2; j++) { if (nums1[i - 1] == nums2[j - 1]) { dp[i][j] = dp[i - 1][j - 1] + 1; } else { dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]); } } } return dp[len1][len2]; } }

53. 最大子序和

class Solution { public int maxSubArray(int[] nums) { int result = Integer.MIN_VALUE; int count = 0; for (int i = 0; i < nums.length; i++) { count += nums[i]; result = Math.max(result, count); if (count <= 0) { count = 0; } } return result; } }

392.判断子序列

class Solution { public boolean isSubsequence(String s, String t) { boolean[] dp = new boolean[s.length() + 1]; dp[0] = true; for (int i = 0; i < t.length(); i ++) { for (int j = dp.length - 1; j > 0; j --) { if (t.charAt(i) == s.charAt(j - 1)) { dp[j] = dp[j - 1]; } } } return dp[dp.length - 1]; } }