// Print all elements in a vector
fn print_vec(arr: &Vec<i32>) {
for n in arr {
print!("{} ", n);
}
println!();
}
// Calculate how many days you must wait for a warmer temperature
fn number_of_days_to_wait(temperatures: &Vec<i32>) -> Vec<i32> {
let size = temperatures.len();
let mut result = vec![0; size];
let mut stack: Vec<usize> = Vec::with_capacity(size); // stack of indices
for i in 0..size {
// While the current temperature is warmer than the temperature
// at the index stored at the top of the stack:
while let Some(&top_idx) = stack.last() {
if temperatures[i] > temperatures[top_idx] {
stack.pop();
result[top_idx] = (i - top_idx) as i32;
} else {
break;
}
}
// Push the current index onto the stack
stack.push(i);
}
// Remaining indices in the stack have no warmer future day
// (result already contains zeros)
result
}
fn main() {
let temperatures = vec![82, 84, 81, 58, 85, 89, 75, 71];
// 82 -> 84 = 1
// 84 -> 81 -> 58 -> 85 = 3
// 81 -> 58 -> 85 = 2
// 58 -> 85 = 1
// 85 -> 89 = 1
// 89 -> 75 -> 71 = 0
// 75 -> 71 = 0
let result = number_of_days_to_wait(&temperatures);
print_vec(&result);
}
/*
run:
1 3 2 1 1 0 0 0
*/
