> #include <stdio.h>
> 
> 
> int main(void) {
> 
> 
> 	int N, A[100010], K;
> 
> 	int i, min = 1, max = 0, mid, sum;
> 
> 
> 	scanf("%d", &N);
> 	for(i = 1; i <= N; i++) {
> 		scanf("%d", &A[i]);
> 		if(A[i] > max) max = A[i];
> 	}
> 	scanf("%d", &K);
> 
> 
> 	if(K <= 1) {printf("%d\n", max); return 0;}
> 
> 	while(min < max) {
> 
> 		mid = (min + max) / 2;
> 
> 		sum = 0;
> 		for(i = 1; i <= N; i++) {
> 			if(A[i] > mid) {
> 				sum += (A[i] - mid) / (K - 1);
> 				if((A[i] - mid) % (K - 1)) sum++;
> 			}
> 		}
> 
> 		if(sum <= mid) {
> 			max = mid;
> 		} else {
> 			min = mid + 1;
> 		}
> 
> 	}
> 
> 
> 	printf("%d\n", max);
> 
> 
> 	return 0;
> 
> 
> }
> 
> Where is the problem?