UVALive 6697 Homework Evaluation

Homework Evaluation

Time Limit: 3000ms

Memory Limit: 131072KB

This problem will be judged on UVALive. Original ID: 6697
64-bit integer IO format: %lld      Java class name: Main

 

 

解题：dp或者dp

$O(n^3)算法$

#include <bits/stdc++.h>
using namespace std;
const int maxn = 200;
int dp[maxn][maxn];
char sa[maxn],sb[maxn];
int main() {
    int kase,a,b;
    scanf("%d",&kase);
    while(kase--) {
        scanf("%s%s",sa,sb);
        a = strlen(sa);
        b = strlen(sb);
        memset(dp,0,sizeof dp);

        int ans = -0x3f3f3f3f;
        for(int i = 1; i <= b; ++i) dp[0][i] = -3*i - 4;
        for(int i = 1; i <= a; ++i) {
            for(int j = 1; j <= b; ++j) {
                if(sa[i-1] == sb[j-1]) dp[i][j] = dp[i-1][j-1] + 8;
                else dp[i][j] = dp[i-1][j-1] - 5;
                for(int k = 0; k < i; ++k)
                    dp[i][j] = max(dp[i][j],dp[k][j] - 4 - (i - k)*3);
                for(int k = 0; k < j; ++k)
                    dp[i][j] = max(dp[i][j],dp[i][k] - 4 - (j - k)*3);
            }
            ans = max(ans,dp[i][b]);
        }
        cout<<ans<<endl;
    }
    return 0;
}

$O(n^2)算法$

#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;

const int maxn = 200;
int dp[maxn][maxn][2];
char sa[maxn],sb[maxn];
int main() {
    int kase;
    scanf("%d",&kase);
    while(kase--) {
        scanf("%s%s",sa,sb);
        int a = strlen(sa);
        int b = strlen(sb);
        memset(dp,-0x3f,sizeof dp);
        int ret = -INF;
        dp[0][0][1] = 0;
        for(int i = 1; i <= a; ++i) {
            dp[i][0][1] = 0;
            for(int j = 1; j <= b; ++j) {
                int tmp = sa[i-1] == sb[j-1]?8:-5;
                dp[i][j][1] = tmp + max(dp[i-1][j-1][0],dp[i-1][j-1][1]);
                dp[i][j][0] = max(dp[i-1][j][1] - 7,dp[i-1][j][0] - 3);
                dp[i][j][0] = max(dp[i][j][0],dp[i][j-1][1] - 7);
                dp[i][j][0] = max(dp[i][j][0],dp[i][j-1][0] - 3);
            }
            ret = max(ret,dp[i][b][1]);
        }
        cout<<ret<<endl;
    }
    return 0;
}