문자열 + 이진탐색

BOJ)1764.cpp

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
using namespace std;
#define MAX_N 500001
char hear[MAX_N][21];
char see[21];
char hearsee[MAX_N][21];
int cmp(const void *a, const void *b) {
	return strcmp((char *)a, (char *)b);
}

int main()
{
	int n, m;
	scanf("%d %d", &n, &m);
	for (int i = 0; i < n; i++) {
		scanf("%s", hear[i]);
	}
	qsort(hear, n, sizeof(hear[0]), cmp);
	int cnt = 0;
	for (int i = 0; i < m; i++) {
		scanf("%s", see);
		if (bsearch(see, hear, n, 21, cmp) != NULL) {
			strcpy(hearsee[cnt++],see);
		}
	}

	qsort(hearsee, cnt, sizeof(hearsee[0]), cmp);
	printf("%d\n", cnt);
	for (int i = 0; i < cnt; i++) {
		printf("%s\n", hearsee[i]);
	}
	return 0;
}