Codeforces 468A 24 Game(构造)

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题目链接：Codeforces 468A 24 Game

题目大意：给出n，表示有1~n这n个数，判断能否进n-1次操作获得24.

解题思路：4,5的情况可以手动处理出来，然后对于大于4，5的情况可以通过两两相减，形成若干个1.

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;int main () {    int n;    scanf("%d", &n);    if (n < 4)        printf("NO\n");    else {        printf("YES\n");        if (n&1) {            printf("4 * 5 = 20\n");            printf("20 + 3 = 23\n");            printf("23 + 2 = 25\n");            printf("25 - 1 = 24\n");            for (int i = 6; i <= n; i += 2) {                printf("%d - %d = 1\n", i + 1, i);                printf("24 * 1 = 24\n");            }        } else {            int c = 1;            for (int i = 2; i <= 4; i++) {                printf("%d * %d = %d\n", c, i, c * i);                c = c * i;            }            for (int i = 5; i <= n; i += 2) {                printf("%d - %d = 1\n", i + 1, i);                printf("24 * 1 = 24\n");            }        }    }    return 0;}

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