55 lines
1.6 KiB
Rust
55 lines
1.6 KiB
Rust
/*
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* File: subset_sum_i_naive.rs
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* Created Time: 2023-07-09
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* Author: codingonion (coderonion@gmail.com)
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*/
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/* Backtracking algorithm: Subset Sum I */
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fn backtrack(
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mut state: Vec<i32>,
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target: i32,
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total: i32,
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choices: &[i32],
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res: &mut Vec<Vec<i32>>,
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) {
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// When the subset sum equals target, record the solution
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if total == target {
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res.push(state);
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return;
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}
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// Traverse all choices
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for i in 0..choices.len() {
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// Pruning: if the subset sum exceeds target, skip that choice
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if total + choices[i] > target {
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continue;
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}
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// Attempt: make a choice, update elements and total
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state.push(choices[i]);
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// Proceed to the next round of selection
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backtrack(state.clone(), target, total + choices[i], choices, res);
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// Retract: undo the choice, restore to the previous state
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state.pop();
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}
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}
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/* Solve Subset Sum I (including duplicate subsets) */
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fn subset_sum_i_naive(nums: &[i32], target: i32) -> Vec<Vec<i32>> {
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let state = Vec::new(); // State (subset)
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let total = 0; // Subset sum
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let mut res = Vec::new(); // Result list (subset list)
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backtrack(state, target, total, nums, &mut res);
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res
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}
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/* Driver Code */
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pub fn main() {
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let nums = [3, 4, 5];
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let target = 9;
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let res = subset_sum_i_naive(&nums, target);
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println!("Input array nums = {:?}, target = {}", &nums, target);
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println!("All subsets equal to {} res = {:?}", target, &res);
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println!("Please note that the result of this method includes duplicate sets");
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}
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