Problem:
We have an array of heights, representing the altitude along a walking trail. Given start/end indexes into the array, return the sum of the changes for a walk beginning at the start index and ending at the end index. For example, with the heights {5, 3, 6, 7, 2} and start=2, end=4 yields a sum of 1 + 5 = 6. The start end end index will both be valid indexes into the array with start <= end.
sumHeights({5, 3, 6, 7, 2}, 2, 4) → 6
sumHeights({5, 3, 6, 7, 2}, 0, 1) → 2
sumHeights({5, 3, 6, 7, 2}, 0, 4) → 11
Solution:
public int sumHeights(int[] heights, int start, int end) {
int tmp = 0;
for (int i = start; i <= end-1; i++) {
tmp += Math.abs(heights[i] - heights[i+1]);
}
return tmp;
}
public int sumHeights(int[] heights, int start, int end) {
ReplyDeleteint sum=0;
for(int i=start;i<end;i++){
int x=Math.abs(heights[i]-heights[i+1]);
sum=sum+x;
}
return sum;
}
Recursive way to look at it.
ReplyDeletepublic int sumHeights(int[] heights, int start, int end) {
if (start >= end) return 0;
return Math.abs(heights[start] - heights[start+1]) + sumHeights(heights, start+1, end);
}