#include<bits/stdc++.h>
//#include "grader.h"
using namespace std;
pair<int,int> D[150001][31][2];
pair<int,int> mn[150001][2];
vector<pair<int,int>> adj[150001];
void count_routes(int N, int M, int P, int R[][2], int Q, int G[]){
for (int i = 0; i < M; i++) {
R[i][0]++;
R[i][1]++;
adj[R[i][0]].push_back({R[i][1],i + 1});
adj[R[i][1]].push_back({R[i][0],i+1});
}
for (int i = 1; i <= N; i++) {
if (adj[i].size() == 1) mn[i][0] = {adj[i][0].second,adj[i][0].first}, mn[i][1] = {adj[i][0].second,adj[i][0].first};
else mn[i][0] = {adj[i][0].second,adj[i][0].first}, mn[i][1] = {adj[i][1].second,adj[i][1].first};
}
for (int i = 1; i <= N; i++) {
D[i][0][0] = {mn[i][0].second,mn[i][0].first};
D[i][0][1] = {mn[i][1].second,mn[i][1].first};
}
for (int j = 1; j <= 30; j++) {
for (int i = 1; i <= N; i++) {
auto S = D[i][j-1][0];
int x = S.first;
int val = S.second;
if (val == mn[x][0].first) {
D[i][j][1] = D[x][j-1][1];
}
else D[i][j][0] = D[x][j-1][0];
S = D[i][j-1][1];
x = S.first;
val = S.second;
if (val == mn[x][0].first)
D[i][j][1] = D[x][j-1][1];
else D[i][j][0] = D[x][j-1][0];
}
}
for (int q = 0,k; q < Q; q++) {
k = G[q] + 1;
pair<int,int> cur;
int ans = 0;
for (int i = 1; i <= N; i++) {
cur = {i,0};
for (int j = 0; j <= 30; j++)
if (k & (1<< j) )
if (cur.second != mn[cur.first][0].first)
cur = D[cur.first][j][0];
else cur = D[cur.first][j][1];
if (cur.first == P) ans ++;
}
answer(ans);
}
}
Compilation message
garden.cpp: In function 'void count_routes(int, int, int, int (*)[2], int, int*)':
garden.cpp:49:9: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
if (k & (1<< j) )
^
garden.cpp:55:9: error: 'answer' was not declared in this scope
answer(ans);
^~~~~~
garden.cpp:55:9: note: suggested alternative: 'ans'
answer(ans);
^~~~~~
ans
