1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93

#![allow(dead_code)]

// sliding window
pub fn min_sub_array_len(s: i32, nums: Vec<i32>) -> i32 {
    let mut i = 0;
    let mut j = 0;
    let mut sum = 0;
    let mut count = nums.len() + 1;
    loop {
        let old_i = i;
        let old_j = j;
        if j < nums.len() && sum < s {
            sum += nums[j];
            j += 1;
            continue;
        }
        if sum >= s && count > j - i {
            count = j - i;
        }
        if sum >= s {
            sum -= nums[i];
            i += 1;
        }
        // no move
        if old_i == i && old_j == j {
            break;
        }
    }

    if i == 0 {
        0
    } else {
        count as i32
    }
}

// other expression
pub fn min_sub_array_len2(s: i32, nums: Vec<i32>) -> i32 {
    if nums.len() < 1 {
        return 0;
    }

    let mut i = 0;
    let mut j = 0;
    let mut sum = 0;
    let mut count = nums.len() + 1;
    while i < nums.len() {
        if j < nums.len() && sum < s {
            sum += nums[j];
            j += 1;
        } else {
            sum -= nums[i];
            i += 1;
        }

        if sum >= s {
            count = count.min(j - i);
        }
    }

    if count == nums.len() + 1 {
        0
    } else {
        count as i32
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test1() {
        assert_eq!(min_sub_array_len(7, vec![2, 3, 1, 2, 4, 3]), 2);
        assert_eq!(
            min_sub_array_len(15, vec![5, 1, 3, 5, 10, 7, 4, 9, 2, 8]),
            2
        );
        assert_eq!(min_sub_array_len(7, vec![3, 2, 1]), 0);
        assert_eq!(min_sub_array_len(7, vec![]), 0);
    }

    #[test]
    fn test2() {
        assert_eq!(min_sub_array_len2(7, vec![2, 3, 1, 2, 4, 3]), 2);
        assert_eq!(
            min_sub_array_len2(15, vec![5, 1, 3, 5, 10, 7, 4, 9, 2, 8]),
            2
        );
        assert_eq!(min_sub_array_len2(7, vec![3, 2, 1]), 0);
        assert_eq!(min_sub_array_len2(7, vec![]), 0);
    }
}