[洛谷P2264]情书

题目传送门

这道题实际上比较简单。简单模拟+字符串处理即可。

#include <bits/stdc++.h>

using namespace std;

#define re register
#define rep(i, a, b) for (re int i = a; i <= b; ++i)
#define repd(i, a, b) for (re int i = a; i >= b; --i)
#define maxx(a, b) a = max(a, b);
#define minn(a, b) a = min(a, b);
#define LL long long
#define inf (1 << 30)

int n;
char text[1010], word[105][60], b[105], ans = 0;

int main() {
    scanf("%d", &n);
    rep(i, 1, n) {
        scanf("%s", word[i]);
        int L = strlen(word[i]);
        rep(x, 0, L-1)
            if (word[i][x] >= 'A' && word[i][x] <= 'Z') word[i][x] -= 'A' - 'a';
    }
    //scanf("%s
", text);
    getchar();
    gets(text);

    int L = strlen(text), p = 0;
    while (p < L) {
        int s = p;
        while (p < L && text[p] != '.') {
            if (text[p] >= 'A' && text[p] <= 'Z') text[p] -= 'A' - 'a';
            else if (text[p] < 'a' || text[p] > 'z') text[p] = ' ';
            p++;
        }
        text[p] = ' ';
        memset(b, 0, sizeof(b));
        rep(i, 1, n) {
            if (b[i]) continue;
            int l = strlen(word[i]);
            rep(x, s, p-l) {
                if (x && text[x-1] != ' ' || text[x+l] != ' ') continue;
                int flag = 1;
                rep(j, 0, l-1)
                    if (word[i][j] != text[x+j]) {
                        flag = 0;
                        break;
                    }
                if (flag) {
                    b[i] = 1;
                    break;
                }
            }                
        }
        rep(i, 1, n) if (b[i]) ans++;
        p++;
    }

    printf("%d", ans);

    return 0;
}

我在做这道题时，RE了2个点。

原因在于text的最后并不是以$.$结尾。总之要注意细节。