hdu 5375 Gray code 【 dp 】

dp[i][j]表示第i位取j的时候取得的最大的分数

然后分s[i]是不是问号，s[i-1]是不是问号这大的四种情况讨论

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

const int maxn = 200005;
int dp[maxn][3];
int a[maxn];
char s[maxn];
int n;

int main(){
    int T;
    scanf("%d",&T);
    int kase = 0;
    while(T--){
        cin >> (s+1);
        n = strlen(s+1);
        for(int i = 1;i <= n;i++) scanf("%d",&a[i]);
        
        s[0] = '0';
        memset(dp,0,sizeof(dp));
        
        for(int i = 1;i <= n;i++){
            if(s[i] == '?'){
                if(s[i-1] == '?'){
                    dp[i][0] = max(dp[i-1][1] + a[i],dp[i-1][0]);
                    dp[i][1] = max(dp[i-1][0] + a[i],dp[i-1][1]);
                }
                else{
                    if(s[i-1] == '0') dp[i][0] = dp[i-1][0],dp[i][1] = dp[i-1][0] + a[i];
                    else dp[i][0] = dp[i-1][1] + a[i],dp[i][1] = dp[i-1][1];
                }
            }
            else{
                if(s[i-1] == '?'){
                    if(s[i] == '0') dp[i][0] = max(dp[i-1][0],dp[i-1][1] + a[i]);
                    else dp[i][1] = max(dp[i-1][0] + a[i],dp[i-1][1]);
                }
                else{
                    if(s[i] == s[i-1]) dp[i][s[i]-'0'] = dp[i-1][s[i-1]-'0'];
                    else dp[i][s[i]-'0'] = dp[i-1][s[i-1]-'0'] + a[i];
                }
            }
        //    printf("dp[%d][0] = %d   dp[%d][1] = %d
",i,dp[i][0],i,dp[i][1]);
        }
        printf("Case #%d: ",++kase);
        if(s[n] == '?') printf("%d
",max(dp[n][0],dp[n][1]));
        else printf("%d
",dp[n][s[n]-'0']);
    }
    return 0;
}

话说比赛的时候，题目的意思都没有读懂------

诶---

加油啊---goooooo---