Submission #406820

#	Time	Username	Problem	Language	Result	Execution time	Memory
406820		amunduzbaev	Bridges (APIO19_bridges)	C++14	29 / 100	179 ms	20632 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

*/

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";
			}
		}
	} else assert(0);
}

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