题解 | #【模板】队列#使用循环队列进行操作

#include <stdio.h>
#include <string.h>
#define maxsize 100000
typedef struct {
    int data[maxsize];
    int front, rear;
} SqQueue;
void initQueue(SqQueue* Q) {
    Q->front = Q->rear = 0;
}
int enQueue(SqQueue* Q, int x) {
    if ((Q->rear + 1) % maxsize == Q->front)
        return 0;
    Q->data[Q->rear] = x;
    Q->rear = (Q->rear + 1) % maxsize;
    return 1;
}
int DeQueue(SqQueue* Q, int* x) {
    if (Q->front == Q->rear) {
        printf("error\n");
        return 0;
    }
    *x = Q->data[Q->front];
    Q->front = (Q->front + 1) % maxsize;
    return 1;
}
int read(SqQueue* Q) {
    if (Q->front == Q->rear) {
        printf("error\n");
        return 0;
    }
    printf("%d\n", Q->data[Q->front]);
    return 1;
}
int main() {
    SqQueue Q;
    initQueue(&Q);
    int n, i = 1;
    char s[1000];
    int k;
    scanf("%d", &n);
    while (i <= n) {
        scanf("%s %d", s, &k);
        if (strcmp(s, "push") == 0) {
            enQueue(&Q, k);
        }
        if (strcmp(s, "pop") == 0) {
            if (DeQueue( &Q, &k) == 1) {
                printf("%d\n", k);
            }
        }
        if (strcmp(s, "front") == 0) {
            read(&Q);
        }
        i++;
    }
    return 0;
}