#128. 【2020.11.26 NOIP模拟赛 T2】等差数列

https://sjzezoj.com/submission/17705

S2OJ/128/128.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, w, a[300005], t[3000005], ans;
+
+int main() {
+    cin >> n >> w;
+    if (n == 1) {
+        cout << 0 << endl;
+        exit(0);
+    }
+    for (int i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+    for (int d = 0; (n - 1) * d <= w; d++) {
+        for (int i = 0; i < n; i++) {
+            if (a[i] > d * i && a[i] + (n - i + 1) * d <= w) {
+                ans = max(ans, ++t[a[i] - d * i]);
+            }
+        }
+        for (int i = 0; i < n; i++) {
+            if (a[i] > d * i) {
+                t[a[i] - d * i] = 0;
+            }
+        }
+    }
+    cout << n - ans << endl;
+    return 0;
+}