Problem: http://codeforces.com/contest/1262/problem/A
Solution: Greedy
- While reading input data, compare and record the maximum value (mxl) of the left bound and the minimum value (mnr) of the right bound of each segment.
- [mnr, mxl], as a result, is the required segment.
- Output 0 (zero) if mxl is less than mnr.
#include <iostream>
using namespace std;
int main() {
int m, n, mxl, mnr, l, r;
cin >> m;
while (m--){
while (cin >> n){
mxl = 0;
mnr = 0x7FFFFFFF;
while (n--){
cin >> l >> r;
mxl = max(mxl, l);
mnr = min(mnr, r);
}
if ((mxl - mnr) > 0) cout << mxl - mnr << "\n";
else cout << 0 << "\n";
}
}
}