12108 - Extraordinarily Tired Students （UVA）

题目链接如下：

Online Judge

开始的代码如下：

#include 
#include 
#include 
// #define debug
 
struct stu{
    int a;
    int b;
};
int n, pos, cnt, kase = 0;
 
int main(){
    #ifdef debug
    freopen("0.txt", "r", stdin);
    freopen("1.txt", "w", stdout);
    #endif
    while(scanf("%d", &n) == 1 && n){
        std::vector vec(n);
        std::setint>> st;
        cnt = 0;
        std::vector<int> state(n);
        for(int i = 0; i < n; ++i){
            scanf("%d %d %d", &vec[i].a, &vec[i].b, &state[i]);
            if(state[i] > vec[i].a){
                ++cnt;
            }
        }
        st.insert(state);
        pos = 1;
        while(cnt){
            int tmp = 0;
            for(int i = 0; i < n; ++i){
                if(2 * cnt <= n && state[i] == vec[i].a){
                    state[i] = 1;
                } else{
                    state[i] = state[i] % (vec[i].a + vec[i].b) + 1;
                    if(state[i] > vec[i].a){
                        tmp++;
                    }
                }
            }
            if(st.find(state) != st.end()){
                pos = -1;
                break;
            }
            st.insert(state);
            cnt = tmp;
            pos++;
        }
        printf("Case %d: %d\n", ++kase, pos);
    }
    #ifdef debug
    fclose(stdin);
    fclose(stdout);
    #endif
    return 0;
}

写完后又看了下其他人的代码，感觉还可以简化一点。也即，只需要把最先的状态init记录下来，重复回到那个状态就判-1，不用引入set那么麻烦。修改后代码如下：

#include 
#include 
// #define debug
 
struct stu{
    int a;
    int b;
};
int n, pos, cnt, kase = 0;
 
int main(){
    #ifdef debug
    freopen("0.txt", "r", stdin);
    freopen("1.txt", "w", stdout);
    #endif
    while(scanf("%d", &n) == 1 && n){
        std::vector vec(n);
        std::vector<int> init;
        cnt = 0;
        std::vector<int> state(n);
        for(int i = 0; i < n; ++i){
            scanf("%d %d %d", &vec[i].a, &vec[i].b, &state[i]);
            init.push_back(state[i]);
            if(state[i] > vec[i].a){
                ++cnt;
            }
        }
        pos = 1;
        while(cnt){
            int tmp = 0;
            for(int i = 0; i < n; ++i){
                if(2 * cnt <= n && state[i] == vec[i].a){
                    state[i] = 1;
                } else{
                    state[i] = state[i] % (vec[i].a + vec[i].b) + 1;
                    if(state[i] > vec[i].a){
                        tmp++;
                    }
                }
            }
            if(init == state){
                pos = -1;
                break;
            }
            cnt = tmp;
            pos++;
        }
        printf("Case %d: %d\n", ++kase, pos);
    }
    #ifdef debug
    fclose(stdin);
    fclose(stdout);
    #endif
    return 0;
}