complete jungol//2194.cpp and fix it

storage/jungol/cpp/completed/2194.cpp

@@ -0,0 +1,43 @@
+#include <algorithm>
+#include <iostream>
+#include <vector>
+
+#define let auto
+#define fn auto
+#define usize size_t
+using namespace std;
+
+#define LIMIT (((usize) 1 << 63) - 1);
+
+fn fastio() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+}
+
+fn main() -> int {
+    fastio();
+    usize n, s;
+    cin >> n >> s;
+    let costs = vector<usize>(n);
+    let yopps = vector<usize>(n);
+    // it needs cost S for storing 1 litre of milk for a week.
+    let cummin = vector<usize>(n);
+
+    for (usize i = 0; i < n; i++) {
+        cin >> costs[i] >> yopps[i];
+    }
+
+    let curr_min = (usize) LIMIT;
+
+    for (usize i = 0; i < n; i++) {
+        curr_min = min(curr_min + s, costs[i]);
+        cummin[i] = curr_min;
+    }
+
+    let total = (usize) 0;
+    for (usize i = 0; i < n; i++) {
+        total += cummin[i] * yopps[i];
+    }
+
+    cout << total << endl;
+}