Submission #498637

#	Time	Username	Problem	Language	Result	Execution time	Memory
498637		RambaXGorilla	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	38 ms	5208 KiB

fancyfence

#include<cstdio>
#include<algorithm>
#include<utility>
#include<queue>
using namespace std;
typedef long long ll;
typedef pair <int,int> ii;
#define pq priority_queue
const int modNum = 1000000007;
int N;
int heights[100010];
int widths[100010];
ll prefs[100010];
int smaller[100010];
pq <ii> big;
int form(ll a, ll b){
    ll nums[] = {a, b, a + 1, b + 1};
    for(int i = 0;i < 4;i++){
        if(!(nums[i] % 2)){
            nums[i] /= 2;
        }
        nums[i] %= modNum;
    }
    ll prod = 1;
    for(int i = 0;i < 4;i++){
        prod *= nums[i];
        prod %= modNum;
    }
    return prod;
}
int main(){
    scanf("%d",&N);
    for(int i = 0;i < N;i++){
        scanf("%d",&heights[i]);
    }
    heights[N] = 0;
    prefs[0] = 0;
    for(int i = 0;i < N;i++){
        scanf("%d",&widths[i]);
        prefs[i + 1] = prefs[i] + widths[i];
    }
    for(int i = 0;i < N + 1;i++){
        while(!big.empty() && big.top().first > heights[i]){
            smaller[big.top().second] = i;
            big.pop();
        }
        big.push(ii(heights[i], i));
    }
    int total = 0;
    for(int i = 0;i < N;i++){
        int bott = 0;
        if(i > 0){
            bott = heights[i - 1];
        }
        int curr = i;
        int last;
        while(curr < N){
            last = curr;
            curr = smaller[curr];
            if(heights[last] <= bott){
                break;
            }
            total += (form(heights[last], prefs[curr] - prefs[i]) - form(max(heights[curr], bott), prefs[curr] - prefs[i]) + modNum) % modNum;
            total %= modNum;
        }
    }
    printf("%d",total);
}

Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     scanf("%d",&N);
      |     ~~~~~^~~~~~~~~
fancyfence.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         scanf("%d",&heights[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~
fancyfence.cpp:39:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |         scanf("%d",&widths[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 18 / 18
• Subtask 7: 27 / 27