1041. Be Unique (20)解题报告

#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>#include <stdlib.h>#define N 10010int main(void) {    int *arr, *arr2, n, i, tmp;    arr = (int *)calloc(N, sizeof(int));    scanf("%d", &n);    arr2 = (int *)calloc(n, sizeof(int));    for (i = 0; i < n; i++) {        scanf("%d", &tmp);        arr[tmp]++;        arr2[i] = tmp;    }    for (i = 0; i < n; i++) {        if (arr[arr2[i]] == 1) {            printf("%d\n", arr2[i]);            break;        }    }    if (i == n) {        puts("None");    }    free(arr);    free(arr2);    return 0;}