#3632. Segment

http://www.nfls.com.cn:20035/submission/591741

NFLSOJ/0/3632/3632.cpp

@@ -0,0 +1,42 @@
+#include <iostream>
+#include <fstream>
+#include <map>
+#include <numeric>
+
+// using std::cin;
+// using std::cout;
+std::ifstream cin("segment.in");
+std::ofstream cout("segment.out");
+const char endl = '\n';
+
+const int N = 5e5 + 5;
+const int mod = 1e9 + 7;
+
+int n;
+long long a[N], s[N], f[N], sum;
+std::map<long long, long long> map;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    std::partial_sum(a + 1, a + 1 + n, s + 1);
+
+    f[0] = sum = 1;
+
+    for (int i = 1; i <= n; i++) {
+        f[i] = sum;
+        sum = ((sum + f[i] - map[s[i]]) % mod + mod) % mod;
+        map[s[i]] = f[i];
+    }
+
+    cout << f[n] << endl;
+
+    return 0;
+}