Prefix Sum· 15 min

Find the Highest Altitude

LeetCode #1732 · Easy · Interactive step-by-step visualization

Setup

Example inputgain = [-5,1,5,0,-7]
Step 1 / 11

Current step

1 / 11

Read gain -5. The next altitude equals the running prefix sum plus this gain. 0 + -5 is ready.

Step log

gain (change per leg)

Cursor
-5
0
1
1
5
2
0
3
-7
4

altitude reached (starts at 0)

0
0

altitude

0

gain

-5

highest

0

Active cursor
Comparing
Best or completed
Leaving or removed
find-the-highest-altitude.java
1public int largestAltitude(int[] gain) {
2    int altitude = 0, highest = 0;
3    for (int delta : gain) {
4        altitude += delta;
5        highest = Math.max(highest, altitude);
6    }
7    return highest;
8}
● Java
Time
O(n)
Space
O(1)
Pattern
array scan
Frames
11
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