new file: 25.cpp

25.cpp

@@ -0,0 +1,23 @@
+// 1055
+#include <cstdio>
+#include <algorithm>
+using namespace std;
+int n;
+int a[100005];
+long long f[100005][2];
+int main()
+{
+    scanf("%d", &n);
+    for (int i = 1; i <= n; ++i)
+    {
+        scanf("%d", &a[i]);
+    }
+    f[1][1] = -a[1];
+    for (int i = 2; i <= n; ++i)
+    {
+        f[i][1] = max(f[i - 1][0] - a[i], f[i - 1][1]);
+        f[i][0] = max(f[i - 1][0], f[i - 1][1] + a[i]);
+    }
+    printf("%d\n", max(f[n][0], f[n][1]));
+    return 0;
+}