```
class Solution {
public:
int coinChange(vector<int>& coins, int amount) {
sort(coins.begin(), coins.end());
vector<int> dp(amount + 1, INT_MAX); dp[0] = 0;
for (int i = 1; i <= amount; ++i) {
for (auto &coin : coins) {
if (coin > i) break;
if (dp[i - coin] == INT_MAX) continue;
dp[i] = std::min(dp[i], dp[i - coin] + 1);
}
}
return dp[amount] == INT_MAX ? -1 : dp[amount];
}
};
```