uva 10118，记忆化搜索
这个题debug了长达3个小时，acm我不能放弃，我又回来了的第一题！
一开始思路正确，写法不行，结果越改越乱
看了网上某神的代码，学习了一下
coding+debug：4小时左右，记忆化搜索+dp类型第一题
/* * Author: Bingo * Created Time: 2015/3/2 21:23:20 * File Name: uva10118.cpp */ #include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <cmath> #include <algorithm> #include <string> #include <vector> #include <stack> #include <queue> #include <set> #include <time.h> using namespace std; const int maxint = -1u>>1; int dp[45][45][45][45]; int a[4][45]; int f[5]; int n; int ans; int ok(int i,int j,int p,int q){ int m[500]; memset(m,0,sizeof(m)); int top=0; for (int t=0;t<i;t++) m[top++]=a[0][t]; for (int t=0;t<j;t++) m[top++]=a[1][t]; for (int t=0;t<p;t++) m[top++]=a[2][t]; for (int t=0;t<q;t++) m[top++]=a[3][t]; sort(m,m+top); int cnt=0,tans=0; for (int t=0;t<top;){ if (m[t]==m[t+1]){ tans++; t+=2; }else { cnt++; t++; } } if (cnt<=5){ ans=max(ans,tans); return 1; } return 0; } int dfs(int i,int j,int p,int q){ if (i==n&&j==n&&p==n&&q==n) return 0; if (i<n){ i++; if(ok(i,j,p,q)) { if (dp[i][j][p][q]){ ans=max(ans,dp[i][j][p][q]); dp[i][j][p][q]=ans; }else {dp[i][j][p][q]=ans;dfs(i,j,p,q);} } } if (j<n){ j++; if(ok(i,j,p,q)) { if (dp[i][j][p][q]){ ans=max(ans,dp[i][j][p][q]); dp[i][j][p][q]=ans; }else {dp[i][j][p][q]=ans;dfs(i,j,p,q);} } } if (p<n){ p++; if(ok(i,j,p,q)) { if (dp[i][j][p][q]){ ans=max(ans,dp[i][j][p][q]); dp[i][j][p][q]=ans; }else {dp[i][j][p][q]=ans;dfs(i,j,p,q);} } } if (q<n){ q++; if(ok(i,j,p,q)) { if (dp[i][j][p][q]){ ans=max(ans,dp[i][j][p][q]); dp[i][j][p][q]=ans; }else {dp[i][j][p][q]=ans;dfs(i,j,p,q);} } } } int main () { while(cin>>n&&n){ for (int i=0;i<n;i++) { cin >> a[0][i]>>a[1][i]>>a[2][i]>>a[3][i]; } memset(dp,0,sizeof(dp)); ans=0; memset(f,0,sizeof(f)); //ok(3,3,3,3); dfs(0,0,0,0); cout << ans<<endl; } return 0; }