oj.uz

답안 #581885

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
581885 2022-06-23T07:42:01 Z 반딧불(#8365) Sparklers (JOI17_sparklers) C++17
0 / 100
 1 ms 340 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int n, k;
ll t;
ll arr[100002];
ll val[100002];
ll revVal[100002];

void makeVector(vector<pair<ll, ll> > &ret, vector<ll> vec){
    ll sum = 0, minSum = 0;
    for(auto x: vec){
        if(sum>0 && x<0){
            ret.push_back(make_pair(-minSum, sum));
            sum = minSum = 0;
        }
        sum += x;
        minSum = min(minSum, sum);
    }
    if(sum || minSum) ret.push_back(make_pair(-minSum, sum));
    ret.push_back(make_pair(5e18, -5e18));
}

bool able(ll speed){
    speed*=t*2;
    if(speed==6){
        #ifdef TEST
        puts("");
        #endif // TEST
    }
    for(int i=1; i<n; i++) val[i] = revVal[n-i] = speed - (arr[i+1] - arr[i]);

    /// ����, ������ �ٵ��
    vector<pair<ll, ll> > Avec, Bvec;
    makeVector(Avec, vector<ll>(revVal+(n+1-k), revVal+n));
    makeVector(Bvec, vector<ll>(val+k, val+n));

    ll val = 0;
    int a = 0, b = 0;
    int al = (int)Avec.size()-1, bl = (int)Bvec.size()-1;

    for(int i=0; i<al-2; i++) assert(Avec[i].second >= 0);
    for(int i=0; i<bl-2; i++) assert(Bvec[i].second >= 0);

    while((a<al && Avec[a].second>=0) || (b<bl && Bvec[b].second>=0)){
        if((a<al && Avec[a].second>=0) && (b<bl && Bvec[b].second>=0)
           && Avec[a].first <= val && Bvec[b].first <= val){ /// �� �� ���� �� ����
            if(Avec[a].second >= Bvec[b].second) val += Avec[a++].second;
            else val += Bvec[b++].second;
        }
        else if((a<al && Avec[a].second>=0) && Avec[a].first <= val){
            val += Avec[a++].second;
        }
        else if((b<bl && Bvec[b].second>=0) && Bvec[b].first <= val){
            val += Bvec[b++].second;
        }
        else return false;
        if(val<0) exit(1);
    }
    if(a>=al && b>=bl) return true;
    else if(a>=al){
        while(b<bl){
            if(Bvec[b].first > val) return false;
            val += Bvec[b++].second;
            if(val<0) return false;
        }
        return true;
    }
    else if(b>=bl){
        while(a<al){
            if(Avec[a].first > val) return false;
            val += Avec[a++].second;
            if(val<0) return false;
        }
        return true;
    }

    assert(a==al-1 && b==bl-1);
    /// �ϳ��� ���� ����
    vector<pair<ll, ll> > vec = {Avec[a], Bvec[b]};
    if(val >= vec[0].first && val+vec[0].second >= vec[1].first && val+vec[0].second+vec[1].second >= 0) return true;
    if(val >= vec[1].first && val+vec[1].second >= vec[0].first && val+vec[1].second+vec[0].second >= 0) return true;
    return false;
}

pair<ll, ll> DP[1002][1002];
ll able2(ll speed){
    speed*=t;
    for(int i=1; i<=n; i++) for(int j=i; j<=n; j++) DP[i][j].first=1e18, DP[i][j].second=-1e18;
    DP[k][k] = make_pair(arr[k], arr[k]);
    for(int d=1; d<n; d++){
        for(int i=1; i+d<=n; i++){
            int j = i+d;
            if((arr[j]-speed*d) <= (DP[i][j-1].second+speed)){
                DP[i][j].first = min(DP[i][j].first, max(arr[j]-speed*d, DP[i][j-1].first-speed));
                DP[i][j].second = max(DP[i][j].second, DP[i][j-1].second+speed);
            }
            if((arr[i]+speed*d) >= (DP[i+1][j].first-speed)){
                DP[i][j].first = min(DP[i][j].first, DP[i+1][j].first-speed);
                DP[i][j].second = max(DP[i][j].second, min(arr[i]+speed*d, DP[i+1][j].second+speed));
            }
        }
    }
    return DP[1][n].first <= DP[1][n].second;
}

int main(){
    scanf("%d %d %lld", &n, &k, &t);
    for(int i=1; i<=n; i++){
        scanf("%lld", &arr[i]);
//        arr[i] = arr[i-1] + rand()%10;
//        printf("%lld ", arr[i]);
    }

    ll L = 0, R = 1e9, ANS = 1e9;
    while(L<=R){
        ll MID = (L+R)/2;
        if(able(MID) != able2(MID)){
            printf("MID %lld: error\n", MID);
            return 1;
        }
        if(able(MID)) ANS = MID, R = MID-1;
        else L = MID+1;
    }
    printf("%lld", ANS);
}

Compilation message

sparklers.cpp: In function 'int main()':
sparklers.cpp:111:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |     scanf("%d %d %lld", &n, &k, &t);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
sparklers.cpp:113:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  113 |         scanf("%lld", &arr[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Runtime error 0 ms 340 KB Execution failed because the return code was nonzero
13 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Runtime error 0 ms 340 KB Execution failed because the return code was nonzero
13 Halted 0 ms 0 KB -

Subtask #3
0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Runtime error 0 ms 340 KB Execution failed because the return code was nonzero
13 Halted 0 ms 0 KB -