some dp problems

CSES - CSES Problem Set/Coin_Combinations_I.cpp

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+//  Coin Combinations I
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+const int MOD = 1e9 + 7;
+ll dp[(int)1e6 + 1];
+
+int main() {
+    int n; int x; cin >> n >> x;
+    dp[0] = 1;
+    vector<int> in(n);
+    for (int i = 0; i < n; i++) cin >> in[i];
+    for (int i = 0; i <= x; ++i) {
+        for (int j = 0; j < n; j++) {
+            if (in[j] <= i) {
+                dp[i] += dp[i - in[j]];
+                dp[i] %= MOD;
+            }
+        }
+    }
+    cout << dp[x] << endl;
+    return 0;
+}