#include<bits/stdc++.h>
using namespace std;
const int K = 20005;
long long cost[K];
int main(){
long long n, t, k;
assert(3 == scanf("%lld %lld %lld",&n,&t,&k));
assert(1 <= n && n <= 1e12);
assert(1 <= t && t <= 5e5);
assert(1 <= k && k <= 2e4);
for(int i=1; i<=k; ++i){
assert(1 == scanf(" %lld",&cost[i]));
}
long long l = cost[1], r = 1e12;
while(l < r){
long long m = (l+r)/2;
long long sum = 0;
for(int i=1; i<=k; ++i){
if(m < cost[i]) break;
long long number = (m-cost[i])/t+1;
if(number >= 1000000){
sum = n;
break;
}
sum += number*(number+1)*2;
}
if(sum >= n) r = m;
else l = m+1;
}
long long ans = 0;
long long sum = 0;
for(int i=1; i<=k; ++i){
if(l-1 < cost[i]) break;
long long number = (l-1-cost[i])/t+1;
ans += cost[i]*number*(number+1)*2;
ans += (number*(number-1)*2)*t;
ans += ((number-1)*(number)*(2*number-1)/6)*4*t;
sum += number*(number+1)*2;
}
ans += (n-sum)*l;
assert(sum <= n);
printf("%lld",ans);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
304 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
308 KB |
Output is correct |
4 |
Correct |
1 ms |
320 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Correct |
7 ms |
588 KB |
Output is correct |
8 |
Correct |
2 ms |
316 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
308 KB |
Output is correct |