Codeforces Round #333 (Div. 1)--b. Lipshitz Sequence monotonic Stack

Test instructions: n points, coordinates are known, where the horizontal axis is 1~n. The maximum value of the slope within all sub-intervals of the interval [L, R].

The first thing to know is that the maximum slope in the [L, R] interval is necessarily the two adjacent points.

Then the problem becomes the same as the maximum of all the sub-intervals in the interval [L, R].

This problem can be done using a monotone stack.

Each time you find the first point to the left of the current point that is greater than the current value, then update the answer. Pose a lot.

1 ImportJava.io.BufferedInputStream;2 ImportJava.io.BufferedOutputStream;3 ImportJava.io.PrintWriter;4 ImportJava.util.Scanner;5 6 7 8  Public classMain {9     StaticScanner cin =NewScanner (NewBufferedinputstream (system.in));Ten     StaticPrintWriter cout =NewPrintWriter (NewBufferedoutputstream (System.out)); One     Static Final intMAXN = 100005; A      Public Static voidMain (string[] args) { -         int[]height =New int[MAXN]; -          while(Cin.hasnext ()) { the             intn =cin.nextint (); -             intQ =cin.nextint (); -Height[0] = 0; -              for(inti = 1; I <= N; i++){ +Height[i] =cin.nextint (); -Height[i-1] = Math.Abs (height[i]-height[i-1]);  +             } A             int[]stack =New int[MAXN]; at             inttop =-1; -              for(inti = 0; i < Q; i++){ -                 intL =cin.nextint (); -                 intR =cin.nextint (); -                 Longres = 0, cur = 0; -top =-1; in                  for(intj = l; J < R; J + +){ -                      while(Top >= 0 && Height[stack[top]] <=Height[j]) { toCur-= 1L * Height[stack[top]] * (stack[top)-(top==0 l-1: stack[top-1])); +top--; -                     } the                     if(Top >= 0){ *Cur + = 1l* (J-stack[top]) *Height[j]; $}Else{Panax NotoginsengCur + = 1L * (j-l + 1) *Height[j]; -                     } theStack[++top] =J; +Res + =cur; A                 } the                  + cout.println (RES);  -             } $ Cout.flush (); $         } -     } -  the}

Codeforces Round #333 (Div. 1)--b. Lipshitz Sequence monotonic Stack