# Cod sursa(job #1975955)

Utilizator Data 2 mai 2017 15:51:53 Heavy Path Decomposition 20 cpp done Arhiva educationala 1.31 kb
``````#include <iostream>
#include <fstream>
#include <vector>

using namespace std;
ifstream f("heavypath.in");
ofstream g("heavypath.out");

const int NMAX = 100005, MMAX = 100005, INF = 0x3f3f3f3f;
int n, m, value[NMAX], father[NMAX], height[NMAX];

vector<int> a[NMAX];

inline void DF(int node)
{
//father[node] = fath;
//height[node] = height[fath] + 1;
for (int i = 0; i < a[node].size(); i++)
{
if (height[a[node][i]] != 0)
continue;
father[a[node][i]] = node;
height[a[node][i]] = height[node] + 1;
DF(a[node][i]);
}
}

inline int max(const int & a, const int & b)
{
if (a < b) return b;
return a;
}

int main()
{
f>>n>>m;
for (int i = 1; i <= n; i++)
f>>value[i];
for (int x, y, i = 1; i < n; i++)
{
f>>x>>y;
a[x].push_back(y);
a[y].push_back(x);
}
height[1] = 1;
DF(1);
int p, x, y;
while(m--)
{
f>>p>>x>>y;
if (p == 0) // update
{
value[x] = y;
} else  // query
{
int Max = max(value[x], value[y]);
while(height[x] > height[y])
{
x = father[x];
Max = max(Max, value[x]);
}
while(height[y] > height[x])
{
y = father[y];
Max = max(Max, value[y]);
}
while (x != y)
{
x = father[x];
y = father[y];
int tempMax = max(value[x], value[y]);
Max = max(Max, tempMax);
}
g<<Max<<'\n';
}
}
f.close();
g.close();
return 0;
}
``````