无法拯救我的菜----徐州网络赛 B. BE, GE or NE

地址：https://nanti.jisuanke.com/t/31454

不会，看的题解。。。。。菜。。。
可以理解为一个人想让最终分数尽可能高，另一个想让最终分数尽可能低，然后根据每个问题双向dp

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int inf = 0x3f3f3f3f;
const int N = 1005;

int dp[N][205];
int a[N],b[N],c[N];
int n,m,k,l;

int dfs(int id,int score)
{
    if(id == n + 1)
        return score;
    if(dp[id][score] != -1)
        return dp[id][score];
    if(id & 1){
        int res = -1;
        if(a[id])
            res = max(res,dfs(id + 1,min(200,score + a[id])));
        if(b[id])
            res = max(res,dfs(id + 1,max(0,score - b[id])));
        if(c[id])
            res = max(res,dfs(id + 1,200 - score));
        dp[id][score] = res;
    }else{
        int res = 300;
        if(a[id])
            res = min(res,dfs(id + 1,min(200,score + a[id])));
        if(b[id])
            res = min(res,dfs(id + 1,max(0,score - b[id])));
        if(c[id])
            res = min(res,dfs(id + 1,200 - score));
        dp[id][score] = res;
    }
    return dp[id][score];
}

int main()
{
    while(~scanf("%d %d %d %d",&n,&m,&k,&l))
    {
        memset(dp,-1,sizeof(dp));
        for(int i = 1;i <= n;++i)
        {
            scanf("%d %d %d",&a[i],&b[i],&c[i]);
        }
        int ans = dfs(1,m + 100);
        if(ans >= k + 100) printf("Good Ending\n");
        else if(ans <= l + 100) printf("Bad Ending\n");
        else printf("Normal Ending\n");
    }
    return 0;
}

用记忆化搜索处理出来每个状态的胜负情况
因为每个人都会选择最优的，因此记忆化搜索的过程其实就是在模拟两个人每一步决策所带来的胜负情况，
只要返回一个必胜，就直接返回（因为会选择最优）
然后在没有返回必胜的状态下，有平局就选择平局，没有平局就只能输了

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int inf = 0x3f3f3f3f;
const int N = 1005;

int dp[N][205];
int a[N],b[N],c[N];
int n,m,k,l;

int dfs(int id,int score)
{
    if(id == n + 1){
        if(score >= k) return 1;
        else if(score <= l) return 3;
        else return 2;
    }
    int &ans = dp[id][score + 100];
    if(ans != -1) return ans;
    bool flag = false;
    if(a[id]){
        int tmp = dfs(id + 1,min(100,score + a[id]));
        if(id & 1){
            if(tmp == 1) return 1;else ans = 3;
        }else{
            if(tmp == 3) return 3;else ans = 1;
        }
        if(tmp == 2) flag = true;
    }
    if(b[id]){
        int tmp = dfs(id + 1,max(-100,score - b[id]));
        if(id & 1){
            if(tmp == 1) return ans = 1;else ans = 3;
        }else{
            if(tmp == 3) return ans = 3;else ans = 1;
        }
        if(tmp == 2) flag = true;
    }
    if(c[id]){
        int tmp = dfs(id + 1,-1 * score);
        if(id & 1){
            if(tmp == 1) return ans = 1;else ans = 3;
        }else{
            if(tmp == 3) return ans = 3;else ans = 1;
        }
        if(tmp == 2) flag = true;
    }
    if(flag) return ans = 2;
    return ans;
}

int main()
{
    while(~scanf("%d %d %d %d",&n,&m,&k,&l))
    {
        memset(dp,-1,sizeof(dp));
        for(int i = 1;i <= n;++i)
        {
            scanf("%d %d %d",&a[i],&b[i],&c[i]);
        }
        int ans = dfs(1,m);
        if(ans == 1) printf("Good Ending\n");
        else if(ans == 3) printf("Bad Ending\n");
        else printf("Normal Ending\n");
    }
    return 0;
}