最长公共子序列模板

#include <bits/stdc++.h>
using namespace std;
const int Maxn = 1011;
int dp[Maxn][Maxn];
int main(){
    string A,B;
    cin >> A >> B;
    int a = A.length(),b = B.length();
    int maxn = -1;
    for( int i = 1; i <= A.length(); i++ ){
        for( int j = 1; j <= B.length(); j++ ){
            if( A[i-1] == B[j-1] ){
                dp[i][j] = dp[i-1][j-1]+1;
            }else if( dp[i][j-1] > dp[i-1][j] ){
                dp[i][j] = dp[i][j-1];
            }else{
                dp[i][j] = dp[i-1][j];
            }
            maxn = max( maxn,dp[i][j] );
        }
    }
    vector<char> v;
    for( int i = a,j = b; i >= 1 && j >= 1; ){
        if( A[i-1] == B[j-1] ){
            v.push_back(A[i-1]);
            i--,j--;
        }else{
            if( dp[i][j-1] > dp[i-1][j] ){
                j--;
            }else{
                i--;
            }
        }
    }
    reverse(v.begin(),v.end());
    for(auto x:v){
        cout << x;
    }
}

 用python实现了一下,吐血了,一个浅拷贝弄得我要死

python定义数组不可以用dp = [[0]*1010]*1010,会有浅拷贝,具体的可以百度一下

下面是python的代码

dp = [([0]*1010) for i in range(1010)]
A = list(raw_input())
B = list(raw_input())
a = len(A)
b = len(B)
for i in range(1,a+1):
    for j in range(1,b+1):
        if A[i-1] == B[j-1]:
            dp[i][j] = dp[i-1][j-1]+1
        else:
            dp[i][j] = max( dp[i-1][j],dp[i][j-1] )


val = []
i = a
j = b
while i >= 1 and j >= 1:
    if A[i-1] == B[j-1]:
        val.append(A[i-1])
        i -= 1
        j -= 1
    else:
        if dp[i][j-1] > dp[i-1][j]:
            j -= 1
        else:
            i -= 1
print "".join(val[::-1])