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UVA 1482 - Playing With Stones(SG打表规律)

UVA 1482 - Playing With Stones

题目链接

题意:给定n堆石头,每次选一堆取至少一个,不超过一半的石子,最后不能取的输,问是否先手必胜

思路:数值很大,无法直接递推sg函数,打出前30项的sg函数找规律

代码:

#include <stdio.h>
#include <string.h>

int t, n;
long long num;

long long SG(long long x) {
	return x % 2 == 0 ? x : SG(x / 2);
}

int main() {
	scanf("%d", &t);
	while (t--) {
		scanf("%d", &n);
		long long ans = 0;
		for (int i = 0; i < n; i++) {
			scanf("%lld", &num);
			ans ^= SG(num);
  		}
  		printf("%s\n", ans == 0 ? "NO" : "YES");
 	}
	return 0;
}