题解 | 【模板】队列

#include <stdio.h>

int main() {
    int n;
    scanf("%d",&n);
    char s[6];
    int x;
    int queue[100000];
    int top = 0;
    int rear = 0;
    for (int i = 0; i < n; i++) {
        scanf("%s", s);
        //printf("%c",s[5]);
        if (s[0] == 'p' && s[1] == 'u') {
            scanf("%d",&x);
            queue[rear] = x;
            rear++;
        }
        if (s[0] == 'p' && s[1] == 'o') {
            if (top == rear) {
        		printf("error\n");
    		} 
		  else {
       		printf("%d\n", queue[top]);
       		top++;
    		}
        }
        if(s[0]=='f'){
            if (top == rear) {
        	printf("error\n");
    	} else {
        	printf("%d\n", queue[top]);
    	}
        }
    }
    return 0;
}