Largest Rectangle in a HistogramHard

Largest Rectangle in a Histogram

HardPractice library · +30 XPmonotonic stackarrays

A histogram has n bars of width 1 and heights h[0..n-1]. Find the area of the largest rectangle that fits inside the histogram (the rectangle covers a run of consecutive bars and its height is limited by the shortest bar in the run).

Input

Line 1: n Line 2: n integers h[i]

Output

One integer: the largest area. It can be as large as 10^14, so use 64-bit integers.

Constraints

  • 1 <= n <= 100000
  • 0 <= h[i] <= 10^9
Time limit 1 s (native code; slower languages get more)Memory 256 MB12 hidden tests

Example 1

Input
6
2 1 5 6 2 3
Output
10

The bars of height 5 and 6 make a rectangle of area 10.

Example 2

Input
2
2 4
Output
4

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