LeetCode 97: Interleaving String 字符串交错

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题目描述

题目地址：https://leetcode.com/problems/interleaving-string/
给定三个字符串 S1 ， S2 ， S3 ，判断 S3 是否能够由 S1 ， S2 交错组合而成。

样例：

S1=aabcc
S2=dbbca
当 S3=aadbbcbcac 时，返回 true
当 S3=aadbbbaccc 时，返回 false

考察点

1. 动态规划

陷阱

无

Code

class Solution {
public:
    bool isInterleave(string s1, string s2, string s3) {
       vector <int> match[2];
        int cur, nxt;
        int l;
        int l1 = s1.length();
        int l2 = s2.length();
        int l3 = s3.length();

        if(l1+l2 != l3)
            return false;

        int *vis[2];

        vis[0] = new int[l1+1];
        vis[1] = new int[l1+1];

        for(int i = 0; i <= l1; i++)
            vis[0][i] = vis[1][i] = -1;

        nxt = 0;
        match[0].push_back(0);

        for(int i = 0; i < l3; i++){
            cur = nxt;
            nxt = !nxt;
            match[nxt].clear();

            for(int k = 0; k < match[cur].size(); k++){

                l = match[cur][k];
                if(l < l1 && s1[l] == s3[i]){

                    if(vis[nxt][l+1] != i){
                        match[nxt].push_back(l+1);
                        vis[nxt][l+1] = i;
                    }
                }

                if(i-l+1 <= l2 && s2[i-l] == s3[i]){

                    if(vis[nxt][l] != i){
                        match[nxt].push_back(l);
                        vis[nxt][l] = i;
                    }
                }
            }
        }
        return !match[nxt].empty();
    }
};

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