Longest Common Substring (K3)
作者:互联网
原题在这里:
https://leetcode.com/discuss/interview-question/1273766/longest-common-substring
这道题跟https://www.cnblogs.com/feiflytech/p/15841611.html 类似,但是不完全相同:
首选自顶向下写个递归,与1143只有一点点不同。
private Integer[][] dp; private int m, n; public int longestCommonSubstring(String text1, String text2) { m = text1.length(); n = text2.length(); dp = new Integer[m][n]; return helper(text1, text2, 0, 0); } private int helper(String text1, String text2, int i, int j) { if (i == m || j == n) return 0; if (dp[i][j] != null) return dp[i][j]; if (text1.charAt(i) == text2.charAt(j)) { if(i+1<m && j+1<n && text1.charAt(i+1)==text2.charAt(j+1)) return dp[i][j] = 1 + helper(text1, text2, i + 1, j + 1); else return 1; } else return dp[i][j] = Math.max( helper(text1, text2, i + 1, j), helper(text1, text2, i, j + 1) ); }
然后自底向上写个dp
public int longestCommonSubstring2(String text1, String text2) { int m = text1.length(); int n = text2.length(); int[][] dp = new int[m+1][n+1]; for (int i = 1; i <= m; i++) { for (int j = 1; j <= n; j++) { if(text1.charAt(i-1)==text2.charAt(j-1)){ if(i-2>=0 && j-2>=0 && text1.charAt(i-2)==text2.charAt(j-2)){ dp[i][j]=1+dp[i-1][j-1]; }else{ dp[i][j]=1; } }else{ dp[i][j]=Math.max(dp[i-1][j], dp[i][j-1]); } } } return dp[m][n]; }
标签:K3,String,int,text2,Substring,text1,Longest,dp,charAt 来源: https://www.cnblogs.com/feiflytech/p/15841621.html