Number of flowers in full bloom

Array Hash Table Binary Search Sorting Prefix Sum Ordered Set

57.7% acceptance

Feb 25, 2026

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You are given a 0-indexed 2D integer array flowers, where flowers[i] = [starti, endi] means the ith flower will be in full bloom from starti to endi (inclusive). You are also given a 0-indexed integer array people of size n, where people[i] is the time that the ith person will arrive to see the flowers. Return an integer array answer of size n, where answer[i] is the number of flowers that are in full bloom when the ith person arrives.

Solution

Rust

Time O(n log n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn full_bloom_flowers(flowers: Vec<Vec<i32>>, people: Vec<i32>) -> Vec<i32> {
    let mut starts: Vec<i32> = flowers.iter().map(|f| f[0]).collect();
    let mut ends: Vec<i32> = flowers.iter().map(|f| f[1]).collect();
    starts.sort_unstable();
    ends.sort_unstable();
    people.iter().map(|&t| {
      // # flowers started by time t: partition_point where start <= t
      let started = starts.partition_point(|&s| s <= t) as i32;
      // # flowers ended before time t: partition_point where end < t
      let ended = ends.partition_point(|&e| e < t) as i32;
      started - ended
    }).collect()
  }
}