#![allow(dead_code)]
pub fn pivot_index(nums: Vec<i32>) -> i32 {
if nums.len() < 2 {
return nums.len() as i32 - 1;
}
let mut i = 0;
let sum: i32 = nums.iter().sum();
let mut half = 0;
while i < nums.len() {
if half * 2 == sum - nums[i] {
return i as i32;
}
half += nums[i];
i += 1;
}
-1
}
pub fn pivot_index2(nums: Vec<i32>) -> i32 {
if nums.len() < 2 {
return nums.len() as i32 - 1;
}
let mut i = 0;
let mut right: i32 = nums.iter().sum();
let mut left = 0;
while i < nums.len() {
right -= nums[i];
if left == right {
return i as i32;
}
left += nums[i];
i += 1;
}
-1
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test1() {
assert_eq!(pivot_index(vec![1, 7, 3, 6, 5, 6]), 3);
assert_eq!(pivot_index(vec![1, 2, 3]), -1);
assert_eq!(pivot_index(vec![-1, -1, -1, -1, -1, 0]), 2);
assert_eq!(pivot_index(vec![-1, -1, -1, 0, 1, 1]), 0);
assert_eq!(pivot_index(vec![0]), 0);
assert_eq!(pivot_index(vec![1, 0]), 0);
assert_eq!(pivot_index(vec![-1, -1, 0, 1, 1, 0]), 5);
}
#[test]
fn test2() {
assert_eq!(pivot_index2(vec![1, 7, 3, 6, 5, 6]), 3);
assert_eq!(pivot_index2(vec![1, 2, 3]), -1);
assert_eq!(pivot_index2(vec![-1, -1, -1, -1, -1, 0]), 2);
assert_eq!(pivot_index2(vec![-1, -1, -1, 0, 1, 1]), 0);
assert_eq!(pivot_index2(vec![0]), 0);
assert_eq!(pivot_index2(vec![1, 0]), 0);
assert_eq!(pivot_index2(vec![-1, -1, 0, 1, 1, 0]), 5);
}
}