ALDS1_3_D Areas on the Cross-Section DiagramをC++で解いてみた[AIZU ONLINE JUDGE]

#include <bits/stdc++.h>
using namespace std;

int main() {
    char c;
    stack<int> s1;
    stack<pair<int, int>> s2;
    int index, top, total, area;

    string str;
    cin >> str;
    //string str = "\\\\//";
    for(int i = 0; i < str.size(); i++) {
        if(str[i] == '\\') {
            s1.push(index);
        } else if(str[i] == '/' && !s1.empty()) {
            top = s1.top();
            s1.pop();
            area = index - top;
            total += area;
            while(!s2.empty() && s2.top().first > top) {
                area += s2.top().second;
                s2.pop();
            }
            s2.push(make_pair(top, area));
        }
        index++;
    }
    cout << total << endl;

    vector<int> list;
    int s2_size = s2.size();
    for(int i = 0; i < s2_size; i++) {
        list.push_back(s2.top().second);
        s2.pop();
    }
    cout << list.size();
    for(int i = list.size() - 1; i >= 0; i--) {
        cout << " " << list.at(i);
    }
    cout << endl;

    return 0;
}