DataStructure_Algorithm/searching.js at main · AthulKrishna-736/DataStructure_Algorithm · GitHub

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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
//searching problems here

//Linear search
function findElem(arr, target) {
    for (let i = 0; i < arr.length; i++) {
        if (arr[i] == target) {
            return i;
        }
    }
    return -1
}

// console.log(findElem([-3, -4, 5, 7, 1, 8, -9], -9))
// console.log(findElem([-3, -4, 5, 7, 1, 8, -9], -21))
// console.log(findElem([-3, -4, 5, 7, 1, 8, -9], 9))


function findBinaryElem(arr, target) {
    let left = 0;
    let right = arr.length - 1

    while (left <= right) {
        let middle = Math.floor((left + right) / 2)
        if (target == arr[middle]) {
            return middle;
        }
        if (target < arr[middle]) {
            right = middle - 1
        } else {
            left = middle + 1
        }
    }
    return -1

}


// console.log(findBinaryElem([1, 2, 3, 4, 5, 6, 9], 3))
// console.log(findBinaryElem([4, 5, 6, 7, 8, 9], 5))

//Time complexity O(log n)

function recursiveBinSearch(arr, target) {
    return search(arr, target, 0, arr.length - 1)
}

function search(arr, target, left, right) {
    if (left > right) {
        return -1
    }
    let middle = Math.floor((left + right) / 2)

    if (target == arr[middle]) {
        return middle;
    }
    if (target < arr[middle]) {
        return search(arr, target, left, middle - 1)
    } else {
        return search(arr, target, middle + 1, right)
    }

}

// console.log(recursiveBinSearch([-5, 2, 4, 6, 10], 10))
// console.log(recursiveBinSearch([-5, 2, 4, 6, 10], 6))
// console.log(recursiveBinSearch([-5, 2, 4, 6, 10], 20))


function find1(arr, target) {
    let left = 0;
    let right = arr.length - 1;
    while (left <= right) {
        let mid = Math.floor((left + right) / 2);

        if (arr[mid] == target) {
            return mid;
        }
        if (target < arr[mid]) {
            right = mid - 1;
        } else {
            left = mid + 1
        }
    }
    return -1;
}

// console.log(find1([2, 3, 4, 5, 6, 7], 3))
// console.log(find1([2, 3, 4, 5, 6, 7], 6))


function find2(arr, target) {
    return findTarget(arr, target, 0, arr.length - 1)
}

function findTarget(arr, target, left, right) {
    if (left > right) {
        return -1;
    }
    let mid = Math.floor((left + right) / 2)
    if (arr[mid] == target) {
        return [target, mid]
    }

    if (target < arr[mid]) {
        return findTarget(arr, target, left, mid - 1)
    } else {
        return findTarget(arr, target, mid + 1, right)
    }
}

// console.log(find2([-5, -3, 4, 8, 9, 13], -3));
// console.log(find2([-5, -3, 4, 8, 9, 13], 13));

function find3(arr, target){
    return findTarget1(arr, target, 0, arr.length - 1)
}

function findTarget1(arr, target, left, right){
    if(left > right){
        return -1
    }
    let mid = Math.floor((left+right)/2)

    if(arr[mid] == target){
        return [target, mid]
    }

    if(target < arr[mid]){
        return findTarget1(arr, target, left, mid - 1)
    } else {
        return findTarget1(arr, target, mid+1, right)
    }
}

console.log(findTarget1([1,2,3,4,5], 40, 0, 5))