Hypyt

input/code.cpp: In function 'int main()':
input/code.cpp:32:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |     for (int i = 0; i < nw.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~

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

int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
  int t; cin>>t;

  while (t--) {
    int n, m; cin>>n>>m;
    if (n * m == 1) continue;
    deque<pair<int, int>> vr;
    for (int x = 0; x < m; x++) {
      for (int y = 0; y < n; y++) {
        vr.push_back({y, x});
      }
    }

    int w = 1;
    vector<pair<int, int>> nw;
    while (!vr.empty()) {
      if (w) {
        nw.push_back(vr[0]);
        vr.pop_front();
      } else {
        nw.push_back(vr.back());
        vr.pop_back();
      }
      w ^= 1;
    }

    for (int i = 0; i < nw.size() - 1; i++) {
      auto a = nw[i];
      auto b = nw[i+1];
      cout << b.first-a.first << " " << b.second - a.second << "\n";
    }
  }
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 2

Verdict: ACCEPTED

Test 4

Group: 2

Verdict: ACCEPTED

Test 5

Group: 2

Verdict: ACCEPTED