Ural_1494. Monobilliards(栈)

　　题意看了老半天，就是说给一个序列[1, n]，看是否是(1, 2, 3, ... n),入栈以后出栈时可以得到的序列。

My Code:

#include <iostream>
#include <cstdio>

using namespace std;

const int N = 100007;

int st1[N], st2[N];

int main() {
    //freopen("data.in", "r", stdin);

    int i, top1, top2, n;
    while(cin >> n) {
        for(i = 0; i < n; i++) {
            cin >> st2[i];
        }
        top1 = 0; top2 = 0;
        for(i = 1; i <= n; i++) {
            st1[++top1] = i;
            while(top1 != 0 && st1[top1] == st2[top2]) {
                --top1; ++top2;
            }
        }
        if(top1)    cout << "Cheater";
        else    cout << "Not a proof";
        cout << endl;
    }
    return 0;
}