Submission #406895

#	Time	Username	Problem	Language	Result	Execution time	Memory
406895		amunduzbaev	Bridges (APIO19_bridges)	C++14	43 / 100	179 ms	20720 KiB

bridges

#include "bits/stdc++.h"
using namespace std;

#define pb push_back
#define int long long
#define ff first
#define ss second

template<class T> bool umin(T& a, const T b) { if(a > b) { a = b; return 1; } return 0; }
template<class T> bool umax(T& a, const T b) { if(a < b) { a = b; return 1; } return 0; }

const int mod = 1e9+7;
const int N = 1e5+5;

int n, m, q, mn[N], dis[N];
vector<pair<int, int>> edges[N];
int tree[3*N];
array<int, 3> tt[N];

void sett(int i, int v, int lx = 0, int rx = m - 1, int x = 1){
	if(lx == rx) { tree[x] = v; return; }
	int m = (lx + rx)>>1;
	if(i <= m) sett(i, v, lx, m, x<<1);
	else sett(i, v, m+1, rx, x<<1|1);
	tree[x] = min(tree[x<<1], tree[x<<1|1]);
}

int flx(int v, int lx, int rx, int x){
	if(lx == rx) return lx;
	int m = (lx + rx)>>1;
	if(tree[x<<1] < v) return flx(v, lx, m, x<<1);
	else return flx(v, m+1, rx, x<<1|1);
}

int find_l(int l, int r, int v, int lx = 0, int rx = m-1, int x = 1){
	if(lx > r || rx < l) return m;
	if(lx >= l && rx <= r){
		if(tree[x] < v) return flx(v, lx, rx, x);
		if(tree[x] >= v) return m;
	} int m = (lx + rx)>>1;
	return min(find_l(l, r, v, lx, m, x<<1), find_l(l, r, v, m+1, rx, x<<1|1));
}

int frx(int v, int lx, int rx, int x){
	if(lx == rx) return lx;
	int m = (lx + rx)>>1;
	if(tree[x<<1|1] < v) return frx(v, m+1, rx, x<<1|1);
	else return frx(v, lx, m, x<<1);
}

int find_r(int l, int r, int v, int lx = 0, int rx = m-1, int x = 1){
	if(lx > r || rx < l) return -1;
	if(lx >= l && rx <= r){
		if(tree[x] < v) return frx(v, lx, rx, x);
		if(tree[x] >= v) return -1;
	} int m = (lx + rx)>>1;
	return max(find_r(l, r, v, lx, m, x<<1), find_r(l, r, v, m+1, rx, x<<1|1));
}

/*

4 3
1 2 3
2 3 4
3 4 4

3
2 1 3
2 2 3
2 3 4

*/

vector<int> is[N];
int par[N], sz[N], rr[N];

int f(int x) { return (x == par[x] ? x : par[x] = f(par[x])); }

void merge(int a, int b){
	a = f(a), b = f(b);
	if(a == b) return;
	if(sz[a] > sz[b]) swap(a, b);
	par[b] = a, sz[a] += sz[b];
}

/*

7 8
1 2 5
1 6 5
2 3 5
2 7 5
3 4 5
4 5 5
5 6 5
6 7 5
7
2 1 6
2 1 2
2 2 2
2 2 4
2 4 2
2 1 1
2 1 3

*/

signed main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin>>n>>m;
	for(int i=0;i<m;i++){
		int a, b, c; cin>>a>>b>>c;
		edges[a].pb({b, c}), edges[b].pb({a, c});
		tt[i] = {a, b, c};
	} cin>>q;
	if(n <= 1000 && m <= 1000 && q <= 10000){
		while(q--){
			int t; cin>>t;
			if(t == 1){
				int br, w; cin>>br>>w, br--;
				int a = tt[br][0], b = tt[br][1], c = tt[br][2]; tt[br][2] = w;
				for(auto& x : edges[a]) if(x.ff == b && x.ss == c) { x.ss = w; break; }
				for(auto& x : edges[b]) if(x.ff == a && x.ss == c) { x.ss = w; break; }
			} else {
				int u, w; cin>>u>>w;
				for(int i=1;i<=n;i++) mn[i] = -mod;
				priority_queue<pair<int, int>> qq;
				mn[u] = mod; qq.push({mod, u});
				while(!qq.empty()){
					auto u = qq.top(); qq.pop();
					if(mn[u.ss] > u.ff) continue;
					for(auto x : edges[u.ss])
						if(umax(mn[x.ff], min(mn[u.ss], x.ss))) qq.push({mn[x.ff], x.ff});
				} int rr = 0;
				for(int i=1;i<=n;i++) if(mn[i] >= w) rr++;
				cout<<rr<<"\n";
			}
		} return 0;
	} 
	
	bool tree = 1;
	for(int i=0;i<m;i++) tree &= (tt[i][0] == (i+1) && tt[i][1] == (i+2));;
	if(tree && n == m + 1){
		for(int i=0;i<m;i++) sett(i, tt[i][2]);
		while(q--){
			int t; cin>>t;
			if(t == 1){
				int i, v; cin>>i>>v;
				sett(i - 1, v);
			} else {
				int i, w; cin>>i>>w, i--;
				int inl = -1, inr = m;
				if(0 <= i-1) inl = find_r(0, i - 1, w);
				if(i <= m-1) inr = find_l(i, m - 1, w);
				cout<<inr - inl<<"\n";
			}
		}
		return 0;
	} if(n == m-1){
		
	} else {
		vector<array<int, 3>> off, ofq;
		for(int i=0;i<m;i++) off.pb({tt[i][2], tt[i][0], tt[i][1]});
		sort(off.begin(), off.end());
		for(int i=0;i<q;i++){
			int t, u, w; cin>>t>>u>>w;
			ofq.pb({w, u, i});
		} sort(ofq.begin(), ofq.end());
		int l = 0;
		
		//cout<<"\n";
		//for(auto x : off) cout<<x[0]<<" "<<x[1]<<" "<<x[2]<<"\n";
		//cout<<"\n";
		//for(auto x : ofq) cout<<x[0]<<" "<<x[1]<<" "<<x[2]<<"\n";
		//cout<<"\n";		
		
		for(int i=0;i<m;){
			while(l < q && ofq[l][0] <= off[i][0]) is[i].pb(l), l++;
			int j = i;
			while(j < m && off[j][0] == off[i][0]) j++;
			i = j;
		} for(int i=1;i<=n;i++) par[i] = i, sz[i] = 1;
		while(l < q) rr[ofq[l][2]] = 1, l++;

		for(int i=m-1;i>=0;i--){
			int j = i;
			while(j >= 0 && off[j][0] == off[i][0]) merge(off[j][1], off[j][2]), j--;
			i = j+1;
			for(auto x : is[i]){
				int in = ofq[x][2], u = ofq[x][1];
				rr[in] = sz[f(u)];
			}
		} 
		//for(int i=0;i<q;i++) assert(rr[i]);
		for(int i=0;i<q;i++) cout<<rr[i]<<" ";
	}
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 0 / 17
• Subtask 4: 14 / 14
• Subtask 5: 0 / 13
• Subtask 6: 0 / 27