Submission #406027

#	Time	Username	Problem	Language	Result	Execution time	Memory
406027		tqbfjotld	The short shank; Redemption (BOI21_prison)	C++14	35 / 100	926 ms	251280 KiB

prison

#include <bits/stdc++.h>
using namespace std;
#define int long long

int range_len[2000005];
pair<int,int> memo[4005][4005];
int N,D,T;

pair<int,int> operator+ (pair<int,int> a, pair<int,int> b){
    return {a.first+b.first,a.second+b.second};
}

pair<int,int> solve(int K){
    for (int x = 0; x<=N; x++){
        memo[N][x] = {0,0};
    }
    for (int x = N-1; x>=0; x--){
        for (int o = 0; o<=N; o++){
            memo[x][o] = memo[x+1][0]+make_pair(K+(range_len[x]>0),1);
            if (o>range_len[x]) memo[x][o] = min(memo[x][o],memo[x+1][o-1]+make_pair(1,0));
            else memo[x][o] = min(memo[x][o],memo[x+1][max(0LL,range_len[x]-1)]+make_pair((range_len[x]>0),0));
            //printf("ans %lld %lld = %lld,%lld\n",x,o,memo[x][o]);
        }
    }
    return memo[0][0];
}

main(){
    scanf("%lld%lld%lld",&N,&D,&T);
    for (int x = 0; x<N; x++){
        int a;
        scanf("%lld",&a);
        range_len[x] = T-a+1;
        if (range_len[x]<0) range_len[x] = 0;
        if (x+range_len[x]>N) range_len[x] = N-x;
    }
    int a = -1;
    int b = N;
    while (a+1<b){
        //printf("try %lld\n",(a+b)/2);
        if (solve((a+b)/2).second>D){
            a = (a+b)/2;
        }
        else b = (a+b)/2;
    }
    pair<int,int> res = solve(b);
    //printf("b = %lld, res = %lld %lld\n",b,res);
    printf("%lld",res.first-res.second*b-b*(D-res.second));
}

Compilation message (stderr)

prison.cpp:28:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   28 | main(){
      | ^~~~
prison.cpp: In function 'int main()':
prison.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |     scanf("%lld%lld%lld",&N,&D,&T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
prison.cpp:32:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         scanf("%lld",&a);
      |         ~~~~~^~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20