message: Update partition-equal-subset-sum.cpp
diff: @@ -12,7 +12,7 @@ public:
  vector<bool> dp(sum / 2 + 1);
  dp[0] = true;
  for (const auto& num : nums) {
  - for (int i = 1; i < dp.size(); ++i) {
  + for (int i = dp.size() - 1; i >= 0; --i) {
  if (num <= i) {
  dp[i] = dp[i] || dp[i - num];
  }
  