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Submission #217690

# Submission time Handle Problem Language Result Execution time Memory
217690 2020-03-30T12:40:10 Z mhy908 Islands (IOI08_islands) C++14
100 / 100
 1115 ms 108536 KB 
#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define F first
#define S second
using namespace std;
typedef long LL;
typedef pair<int, int> pii;
const LL llinf=1987654321987654321;

int n;
LL ret, ans;
vector<pii> link[1000010];
int cyc[1000010], re;
LL sum[1000010];
bool ch[1000010];

inline LL get_cyc(int num, int par){
    if(ch[num]){
        cyc[re]=num;
        sum[re++]=0;
        return 0;
    }
    ch[num]=true;
    bool t=true;
    for(pii i:link[num]){
        if(i.F==par&&t){
            t=false;
            continue;
        }
        LL temp=get_cyc(i.F, num)+i.S;
        if(temp>=0){
            ch[num]=false;
            cyc[re]=num;
            sum[re++]=temp;
            if(cyc[0]==num)return -llinf;
            return temp;
        }
    }
    ch[num]=false;
    return -llinf;
}

inline LL get_maxd(int num, int par1, int par2){
    LL ret2=0;
    ch[num]=true;
    for(pii i:link[num]){
        if(i.F==par1||i.F==par2)continue;
        LL temp=get_maxd(i.F, num, num)+i.S;
        ret=max(ret, ret2+temp);
        ret2=max(ret2, temp);
    }
    return ret2;
}

int main(){
    scanf("%d", &n);
    for(int i=1; i<=n; i++){
        int a, b;
        scanf("%d %d", &a, &b);
        link[i].pb(mp(a, b));
        link[a].pb(mp(i, b));
    }
    for(int j=1; j<=n; j++){
        if(ch[j])continue;
        re=0; ret=0;
        get_cyc(j, 0);
        LL max1=llinf, max2=-llinf, dia=sum[--re];
        for(int i=0; i<re; i++){
            LL tmp=get_maxd(cyc[i], cyc[(i+re-1)%re], cyc[(i+1)%re]);
            ret=max(ret, sum[i]+tmp-max1);
            ret=max(ret, dia-sum[i]+tmp+max2);
            max2=max(max2, sum[i]+tmp);
            max1=min(max1, sum[i]-tmp);
        }
        ans+=ret;
    }
    printf("%lld", ans);
}

Compilation message

islands.cpp: In function 'int main()':
islands.cpp:78:23: warning: format '%lld' expects argument of type 'long long int', but argument 2 has type 'LL {aka long int}' [-Wformat=]
     printf("%lld", ans);
                       ^
islands.cpp:57:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
islands.cpp:60:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 17 ms 23808 KB Output is correct
3 Correct 18 ms 23808 KB Output is correct
4 Correct 19 ms 23808 KB Output is correct
5 Correct 17 ms 23808 KB Output is correct
6 Correct 18 ms 23808 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 17 ms 23808 KB Output is correct
9 Correct 17 ms 23808 KB Output is correct
10 Correct 17 ms 23808 KB Output is correct
11 Correct 18 ms 23808 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 23936 KB Output is correct
2 Correct 18 ms 23808 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23936 KB Output is correct
2 Correct 19 ms 24064 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 24448 KB Output is correct
2 Correct 35 ms 25976 KB Output is correct
3 Correct 29 ms 24576 KB Output is correct
4 Correct 23 ms 24192 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 41 ms 26744 KB Output is correct
2 Correct 60 ms 28412 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 109 ms 32376 KB Output is correct
2 Correct 111 ms 35320 KB Output is correct
3 Correct 135 ms 41336 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 184 ms 39292 KB Output is correct
2 Correct 231 ms 53752 KB Output is correct
3 Correct 257 ms 56952 KB Output is correct
4 Correct 304 ms 68600 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 401 ms 64076 KB Output is correct
2 Correct 753 ms 88584 KB Output is correct
3 Correct 353 ms 54912 KB Output is correct
4 Correct 460 ms 77952 KB Output is correct
5 Correct 442 ms 78456 KB Output is correct
6 Correct 1115 ms 60208 KB Output is correct
7 Correct 464 ms 93432 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 493 ms 96008 KB Output is correct
2 Correct 473 ms 77304 KB Output is correct
3 Correct 498 ms 108536 KB Output is correct
4 Correct 447 ms 56056 KB Output is correct
5 Correct 452 ms 78840 KB Output is correct
6 Correct 463 ms 65272 KB Output is correct
7 Correct 1000 ms 60536 KB Output is correct