Yet Another Ball Problem CodeForces - 1118E (简单构造)

大意: 求构造n个pair, 每个pair满足

对于每k组, 让$b_i$为$[1,k]$, $g_i$循环右移就好了

int n, k, cnt;

int main() {
    scanf("%d%d", &n, &k);
    if (n>(ll)k*(k-1)) return puts("NO"),0;
    puts("YES");
    int cnt = 0;
    REP(i,1,n) {
        int cur = i+1;
        REP(j,1,k) {
            printf("%d %d\n",j,cur);
            if (++cnt==n) return 0;
            if (++cur==k+1) cur = 1;
        }
    }
}