D - Areas on the Cross-Section Diagram Aizu - ALDS1_3_D

#include <bits/stdc++.h>

#define INF 0x3f3f3f3f
#define eps 1e-6

typedef long long LL;
const double pi = acos(-1.0);
const long long mod = 1e9;
using namespace std;

stack<int> s1;
stack<pair<int,int> > s2;
vector<int> ans;

int main()
{
//ios_base::sync_with_stdio(false); cin.tie(0);
//freopen("int.txt","r",stdin);
//freopen("out.txt","w",stdout);
string s;
cin >> s;
int sum = 0;
int len = s.size();
for(int i = 0;i < len;i++)
{
if(s[i] == '\\')
s1.push(i);
else if(s[i] == '/' && s1.size() > 0)
{
int j = s1.top();s1.pop();
sum += i - j;

int a = i - j;
while(s2.size() > 0 && s2.top().first > j)
{
a += s2.top().second;
s2.pop();
}
s2.push(make_pair(j,a));
}
}

while(s2.size() > 0)
{
ans.push_back(s2.top().second);
s2.pop();
}
reverse(ans.begin(),ans.end());
cout << sum << endl;
cout << ans.size();
for(int i = 0;i < ans.size();i++)
cout << ' ' << ans[i];
cout << endl;
return 0;
}