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답안 #273752

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
273752 2020-08-19T07:04:54 Z 문홍윤(#5110) Mountains and Valleys (CCO20_day1problem3) C++17
2 / 25
 27 ms 13568 KB 
#include <bits/stdc++.h>
#define eb emplace_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define svec(x) sort(x.begin(), x.end())
#define press(x) x.erase(unique(x.begin(), x.end()), x.end())
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
typedef pair<LL, LL> pll;
typedef pair<int, LL> pil;
typedef pair<LL, int> pli;
const LL llinf=2e18;
const int inf=1e9;

int n, m, r1, r2;
vector<int> link[500010];
vector<pair<pii, int> > edg;

int dis[500010], sp[500010][30], ans;

void dfs(int num, int par){
    dis[num]=dis[par]+1;
    sp[num][0]=par;
    for(auto i:link[num]){
        if(i==par)continue;
        dfs(i, num);
    }
}
int lca(int x, int y){
    if(dis[x]>dis[y])swap(x, y);
    for(int i=20; i>=0; i--){
        if(dis[y]-dis[x]>=(1<<i))y=sp[y][i];
    }
    if(x==y)return x;
    for(int i=20; i>=0; i--){
        if(sp[x][i]!=sp[y][i]){
            x=sp[x][i];
            y=sp[y][i];
        }
    }
    return sp[x][0];
}
int get_dist(int x, int y){return dis[x]+dis[y]-2*dis[lca(x, y)];}

int dis2[500010], p[500010];
void dfs2(int num, int par){
    dis2[num]=dis2[par]+1;
    p[num]=par;
    for(auto i:link[num]){
        if(i==par)continue;
        dfs2(i, num);
    }
}

vector<int> rt1, rt2;
int h[500010];
bool ch[500010];

void dfs3(int num, int par){
    for(auto i:link[num]){
        if(i==par||ch[i])continue;
        dfs3(i, num);
        h[num]=max(h[num], h[i]+1);
    }
    if(ch[num])rt1.eb(h[num]);
    for(auto i:link[num]){
        if(i==par||!ch[i])continue;
        dfs3(i, num);
    }
}
struct SEGMENT_TREE{
    int tree[2000010];
    int f(int a, int b){return max(a, b);}
    void update(int point, int s, int e, int num, int val){
        if(s==e){
            tree[point]=val;
            return;
        }
        if(num<=(s+e)/2)update(point*2, s, (s+e)/2, num, val);
        else update(point*2+1, (s+e)/2+1, e, num, val);
        tree[point]=f(tree[point*2], tree[point*2+1]);
    }
    int query(int point, int s, int e, int a, int b){
        if(a<=s&&e<=b)return tree[point];
        if(e<a||s>b)return -inf;
        return f(query(point*2, s, (s+e)/2, a, b), query(point*2+1, (s+e)/2+1, e, a, b));
    }
}seg;
int main(){
    scanf("%d %d", &n, &m);
    for(int i=1; i<=m; i++){
        int a, b, c;
        scanf("%d %d %d", &a, &b, &c);
        a++; b++;
        if(c==1){
            link[a].eb(b);
            link[b].eb(a);
        }
        else edg.eb(mp(a, b), c);
    }
    dfs(1, 0);
    for(int j=1; j<=20; j++){
        for(int i=1; i<=n; i++)sp[i][j]=sp[sp[i][j-1]][j-1];
    }
    dfs2(1, 0);
    int r1=max_element(dis2+1, dis2+n+1)-dis2;
    dfs2(r1, 0);
    int r2=max_element(dis2+1, dis2+n+1)-dis2;
    int tmp=r2;
    while(tmp){
        ch[tmp]=true;
        tmp=p[tmp];
    }
    dfs3(r1, 0);
    rt2=rt1;
    for(int i=0; i<dis2[r2]; i++){
        rt1[i]+=i, rt2[i]+=dis2[r2]-1-i;
    }
    for(int i=1; i<dis2[r2]; i++)rt1[i]=max(rt1[i], rt1[i-1]);
    for(int i=dis2[r2]-2; i>=0; i--)rt2[i]=max(rt2[i], rt2[i+1]);
    for(int i=0; i<dis2[r2]-1; i++)seg.update(1, 0, dis2[r2]-2, i, rt1[i]+rt2[i+1]);
    ans=2*(n-1)-dis2[r2]+1;
    for(auto i:edg){
        int d=get_dist(i.F.F, i.F.S);
        if(d<=i.S)continue;
        int nd=2*(n-2)+i.S;
        int r1to1=get_dist(r1, i.F.F)+dis2[r2]-1-get_dist(r2, i.F.F);
        int r1to2=get_dist(r1, i.F.S)+dis2[r2]-1-get_dist(r2, i.F.S);
        r1to1/=2, r1to2/=2;
        if(r1to1>r1to2){
            swap(i.F.F, i.F.S);
            swap(r1to1, r1to2);
        }
        int d1=get_dist(r1, i.F.F);
        int d2=get_dist(r2, i.F.S);
        int h1=d1+get_dist(r2, i.F.F)-dis2[r2]+1;
        int h2=d2+get_dist(r1, i.F.S)-dis2[r2]+1;
        int mk1=d1-h1;
        int mk2=dis2[r2]-1-d2+h2;
        int temp=seg.query(1, 0, dis2[r2]-2, mk1, mk2-1);
        temp+=(-mk1-dis2[r2]+1+mk2);
        ans=min(ans, nd-temp+h1+h2);
    }
    printf("%d", ans);
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:93:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   93 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
Main.cpp:96:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   96 |         scanf("%d %d %d", &a, &b, &c);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 1.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #2
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 13568 KB Output is correct
2 Correct 20 ms 13440 KB Output is correct
3 Correct 27 ms 13312 KB Output is correct
4 Correct 15 ms 13312 KB Output is correct
5 Correct 16 ms 13184 KB Output is correct
6 Correct 14 ms 13056 KB Output is correct
7 Correct 20 ms 13568 KB Output is correct
8 Correct 20 ms 13440 KB Output is correct
9 Correct 20 ms 13440 KB Output is correct
10 Correct 16 ms 13312 KB Output is correct
11 Correct 17 ms 13440 KB Output is correct
12 Correct 15 ms 13312 KB Output is correct
13 Correct 16 ms 13312 KB Output is correct
14 Correct 17 ms 13312 KB Output is correct

Subtask #4
0.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 12288 KB Output is correct
2 Correct 8 ms 12160 KB Output is correct
3 Correct 9 ms 12160 KB Output is correct
4 Correct 8 ms 12160 KB Output is correct
5 Correct 9 ms 12160 KB Output is correct
6 Correct 9 ms 12160 KB Output is correct
7 Correct 8 ms 12160 KB Output is correct
8 Correct 9 ms 12160 KB Output is correct
9 Correct 9 ms 12160 KB Output is correct
10 Correct 8 ms 12160 KB Output is correct
11 Correct 8 ms 12160 KB Output is correct
12 Correct 9 ms 12160 KB Output is correct
13 Correct 8 ms 12160 KB Output is correct
14 Incorrect 8 ms 12160 KB Output isn't correct
15 Halted 0 ms 0 KB -