URAL 1494 Monobilliards (栈)

#include <stdio.h>int stack[100001];int top;int main(){int numOfBalls;scanf("%d", &numOfBalls);top = 0;int ballToPocket = 1;int i;for (i = 1; i <= numOfBalls; i++){int ballTakenOut;scanf("%d", &ballTakenOut);while (stack[top] != ballTakenOut && ballToPocket <= numOfBalls){stack[++top] = ballToPocket;ballToPocket++;}if (top && stack[top] == ballTakenOut)top--;}printf("%s\n", top ? "Cheater" : "Not a proof");return 0;}