Saturday, May 25, 2024

Codeforces Round #427 (Div. 2), problem: (F) Roads in the Kingdom Solution In C/C++

#include <bits/stdc++.h>

using namespace std;

int n;

int to[500000], pre[500000], cost[500000], last[250000], en;

long long wxs;

void addedge(int f, int t, int w)
{
to[++en] = t;
cost[en] = w;
pre[en] = last[f];
last[f] = en;
}

int Stack[250000], vis[250000], top;

int ring[250000], rs;

long long val[250000], edge[250000];

bool dfs(int now, int p)
{
Stack[++top] = now;
vis[now] = top;
for (int i = last[now]; i; i = pre[i])
{
if (to[i] == p)
{
continue;
}
if (vis[to[i]] > 0)
{
for (int j = vis[to[i]]; j <= top; ++j)
{
ring[++rs] = Stack[j];
}
return 1;
}
if (dfs(to[i], now))
{
return 1;
}
}
–top;
vis[now] = 2147483647;
return 0;
}

int taboo1, taboo2;

long long dfs2(int now, int p)
{
long long fir = 0, sec = 0;
for (int i = last[now]; i; i = pre[i])
{
if (to[i] == p)
{
continue;
}
if (to[i] == taboo1)
{
continue;
}
if (to[i] == taboo2)
{
continue;
}
long long th = dfs2(to[i], now) + cost[i];
if (th >= fir)
{
sec = fir;
fir = th;
} else if (th > sec)
{
sec = th;
}
}
wxs = max(wxs, fir + sec);
return fir;
}

long long to_l[250000], to_r[250000];
long long mx_l[250000], mx_r[250000];

long long ans;

int main()
{
scanf(“%d”, &n);
for (int i = 1; i <= n; ++i)
{
int u, v, w;
scanf(“%d%d%d”, &u, &v, &w);
}
dfs(1, 0);
ring[0] = ring[rs];
ring[rs + 1] = ring[1];
long long sum = 0;
for (int i = 1; i <= rs; ++i)
{
taboo1 = ring[i – 1];
taboo2 = ring[i + 1];
val[i] = dfs2(ring[i], 0);
for (int j = last[ring[i]]; j; j = pre[j])
{
if (to[j] == ring[i – 1])
{
edge[i – 1] = cost[j];
sum += cost[j];
}
}
}
edge[rs] = edge[0];
val[0] = val[rs];
val[rs + 1] = val[1];
long long tmp = 0, tmp2 = 0;
for (int i = 1; i <= rs; ++i)
{
to_l[i] = max(to_l[i – 1], tmp + val[i]);
mx_l[i] = max(mx_l[i – 1], tmp2 + val[i]);
tmp += edge[i];
tmp2 = max(tmp2, val[i]) + edge[i];
}
tmp = tmp2 = 0;
for (int i = rs; i >= 1; –i)
{
to_r[i] = max(to_r[i + 1], tmp + val[i]);
mx_r[i] = max(mx_r[i + 1], tmp2 + val[i]);
tmp += edge[i – 1];
tmp2 = max(tmp2, val[i]) + edge[i – 1];
}
ans = mx_l[rs];
for (int i = 1; i < rs; ++i)
{
long long nans = max(to_l[i] + to_r[i + 1] + edge[0], max(mx_l[i], mx_r[i + 1]));
ans = min(ans, nans);
}
ans = max(ans, wxs);
cout << ans << endl;
}

Celebrating Black History Month:...

As February unfolds, so does the annual celebration of...

The Path to Self-Mastery:...

Embarking on a journey of self-mastery and breaking free...

Wizards of Waverly Place...

In a spellbinding announcement, Disney has officially revealed that...

Jim Irsay’s Reported ‘Suspected...

In a shocking turn of events last month, Jim...

Coachella Valley Music and Arts Festival, one of the...

2024 Taiwan Election: Pivotal...

As Taiwan gears up for its 2024 presidential election,...

Celebrating Black History Month: Past, Future

As February unfolds, so does the annual celebration of Black History Month, a time to reflect on the profound contributions, resilience, and rich cultural...

The Path to Self-Mastery: Lessons from Book ‘The Mountain Is You’

Embarking on a journey of self-mastery and breaking free from self-sabotage is a transformative process that requires dedication and conscious effort. Brianna Wiest's insightful...

Wizards of Waverly Place Cast Reunites for Enchanting Revival

In a spellbinding announcement, Disney has officially revealed that the beloved fantasy series "Wizards of Waverly Place" is set for a magical comeback, featuring...

Jim Irsay’s Reported ‘Suspected Overdose’: A Closer Look

In a shocking turn of events last month, Jim Irsay, the owner of the Indianapolis Colts, was reportedly found unresponsive at his home in...

Coachella 2024: Iconic headliners, unforgettable musical experience!

Coachella Valley Music and Arts Festival, one of the most iconic and eagerly anticipated music festivals globally, has just dropped its highly anticipated lineup...

2024 Taiwan Election: Pivotal Moment in Political Landscape

As Taiwan gears up for its 2024 presidential election, the political landscape is buzzing with anticipation and fervor. With the island nation situated at...

Michael Strahan’s Daughter’s Medulloblastoma Diagnosis

In a recent and heartbreaking revelation, Michael Strahan, former NFL star and television personality, shared the devastating news of his daughter Isabella's diagnosis with...

Michigan vs. Washington: The 2024 National Championship Clash

In a highly anticipated matchup, the 2024 National Championship will witness a clash of football titans as the Michigan Wolverines square off against the...

Jason Kelce: Unmasking the Unconventional NFL Icon

In the world of professional football, where conformity often takes center stage, one player stands out as a beacon of individuality, both on and...