25.DNA序列编辑距离（已解决）【记忆化搜索+深度优先】

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>


int dfs (std::vector<std::vector<int>>& memo,std::string dna1, std::string dna2, int i, int j){
    if(i < 0 || j < 0){//当遍历的编号超过范围
        return abs(i - j);
    }
    if(memo[i][j] != -1){
        return memo[i][j];
    }
    if(dna1[i] == dna2[j]){
        memo[i][j] = dfs(memo, dna1, dna2, i-1,j-1);
    }else{
        //增加 删除 替换
        memo[i][j] = std::min({dfs(memo, dna1, dna2, i-1, j) + 1, dfs(memo, dna1, dna2, i,j-1) + 1, dfs(memo, dna1, dna2, i-1,j-1) + 1});
    }
    return memo[i][j];
}


int solution(std::string dna1, std::string dna2) {
    // Please write your code here
    int n1 = dna1.size();
    int n2 = dna2.size();
    std::vector<std::vector<int>> memo(n1, std::vector<int> (n2, -1));

    return dfs(memo, dna1, dna2, dna1.size() - 1, dna2.size() - 1);
}

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