实验二——动态规划·LCS

/*Hatsune Miku 4ever!*/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define _for(i,a,b) for(int i = (a);i < b;i ++)
#define _rep(i,a,b) for(int i = (a);i > b;i --)
#define INF 0x3f3f3f3f
#define mod 1000000007
#define lowbit(x) ((x)&(-x))
#define pb push_back
#define MIKU 39
#define Design ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define debug() printf("Miku Check OK!\n")
#define maxn 339

int n, m;
int dp[maxn][maxn];
pair<int,int> path[maxn][maxn];
string s1, s2;
string ans;
void dfs(int a,int b)
{
    if(!a && !b)
        return ;
    if(s1[a]==s2[b])
        ans += s1[a];
    dfs(path[a][b].first,path[a][b].second);
}

int main()
{
    Design;
    s1 += ‘P‘, s2 += ‘M‘;
    string tmp1, tmp2;
    cin >> tmp1 >> tmp2; 
    s1 += tmp1, s2 += tmp2;
    memset(dp,0,sizeof(dp));
    int n = s1.size(), m = s2.size();
    _for(i,1,n)
        _for(j,1,m)
        {
            if(s1[i]==s2[j])
            {
                if(dp[i-1][j-1]+1 > dp[i][j])
                    path[i][j] = {i-1,j-1};
                dp[i][j] = max(dp[i][j],dp[i-1][j-1]+1);
            }
            else
            {
                if(dp[i][j-1] > dp[i-1][j])
                    path[i][j] = {i,j-1};
                else
                    path[i][j] = {i-1,j};
                dp[i][j] = max(dp[i][j-1],dp[i-1][j]);
            }
        } 
    cout << dp[n-1][m-1] << endl; 
    dfs(n-1,m-1);
    reverse(ans.begin(),ans.end());
    cout << ans << endl;
    return 0;
}