[LeetCode][0004] median of Two Sorted Arrays

LeetCode 2020. 6. 12. 00:27

 

 

 

class Solution {
public:
    double findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2) {
        int nums1_size = nums1.size();
        int nums2_size = nums2.size();
        
        if(nums1_size > nums2_size) {
            return findMedianSortedArrays(nums2, nums1);
        }
        
        int left = 0, right = nums1_size;
        int mid = (nums1_size + nums2_size + 1) / 2;
        
        int max_of_left = -1, min_of_right = -1;
        while(left <= right) {
            int i = (left + right) / 2;
            int j = (mid - i);
            
            if(i < nums1_size && nums1[i] < nums2[j - 1]) {
                left = i + 1;
            } else if(i > 0 && nums1[i - 1] > nums2[j]) {
                right = i - 1;
            } else {
                if(i == 0) {
                    max_of_left = nums2[j - 1];
                } else if(j == 0) {
                    max_of_left = nums1[i - 1];
                } else {
                    max_of_left = max(nums1[i - 1], nums2[j - 1]);
                }
                
                if((nums1_size + nums2_size) % 2 == 1) {
                    return max_of_left;
                }
                
                if(i == nums1_size) {
                    min_of_right = nums2[j];
                } else if(j == nums2_size) {
                    min_of_right = nums1[i];
                } else {
                    min_of_right = min(nums1[i], nums2[j]);
                }
                return (max_of_left + min_of_right) / 2.0;
            }
        }
        return -1.0;
    }
};

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[LeetCode][0003] Longest Substring Without Repeating Characters

LeetCode 2020. 6. 12. 00:25

 

 

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        int left = 0, right = 0, ret = 0;
        unordered_map<char, int> m;
        while(right < s.size()) {
            if(m.find(s[right]) != m.end()) {
                left = max(left, m[s[right]] + 1);
            }
            ret = max(ret, right - left + 1);
            m[s[right]] = right;
            ++right;
        }
        return ret;
    }
};

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[LeetCode][0002] Add Two Numbers

LeetCode 2020. 6. 11. 08:44

 

 

 

 

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        ListNode *dummy = new ListNode(-1);
        
        ListNode* target = dummy;
        int carry = 0;
        while(l1 || l2 || carry) {
            int l1_val = (l1) ? (l1->val) : (0);
            int l2_val = (l2) ? (l2->val) : (0);
            int sum = (l1_val + l2_val + carry);
            target->next = new ListNode(sum % 10);
            carry = sum / 10;
            
            target = target->next;
            l1 = (l1) ? (l1->next) : (l1);
            l2 = (l2) ? (l2->next) : (l2);
        }
        
        return dummy->next;
    }
};

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Linked List

Data Structure 2019. 2. 13. 23:00


#include <stdio.h>
#include <algorithm>
#include <list>
#include "Windows.h"
using namespace std;

struct NODE {
	int prev;
	int next;
	int val;
};

const int NODE_SIZE = 30000;

//TEST CMD
const int PUSH_BACK = 0;
const int PUSH_FRONT = 1;
const int INSERT = 2;
const int POP_BACK = 3;
const int POP_FRONT = 4;
const int ERASE = 5;

int test_cmd[NODE_SIZE][3];

struct MY_LIST {
	int HEAD = NODE_SIZE;
	int TAIL = NODE_SIZE + 1;
	int pos;
	NODE node[NODE_SIZE + 2];

	MY_LIST() {
		pos = 0;
		node[HEAD].next = TAIL;
		node[TAIL].prev = HEAD;
	}

	void push_back(int data) {
		int prev = node[TAIL].prev;
		int next = node[prev].next;	// TAIL;

		node[pos].val = data;

		node[pos].prev = prev;
		node[prev].next = pos;

		node[pos].next = next;
		node[next].prev = pos;
		++pos;
	}

	void push_front(int data) {
		int next = node[HEAD].next;
		int prev = node[next].prev;	// HEAD
		
		node[pos].val = data;

		node[pos].prev = prev;
		node[prev].next = pos;

		node[pos].next = next;
		node[next].prev = pos;
		++pos;
	}

	void insert(int p, int data) {
		int next = node[HEAD].next;
		for(int i = 0; i < p; ++i) {
			next = node[next].next;
		}
		int prev = node[next].prev;
	
		node[pos].val = data;

		node[pos].prev = prev;
		node[prev].next = pos;

		node[pos].next = next;
		node[next].prev = pos;
		++pos;
	}

	void pop_back() {
		int target = node[TAIL].prev;

		int prev = node[target].prev;
		int next = node[target].next;

		node[prev].next = next;
		node[next].prev = prev;
	}

	void pop_front() {
		int target = node[HEAD].next;

		int prev = node[target].prev;
		int next = node[target].next;

		node[prev].next = next;
		node[next].prev = prev;
	}

	void erase(int p) {
		int target = node[HEAD].next;
		for (int i = 0; i < p; ++i) {
			target = node[target].next;
		}
		int prev = node[target].prev;
		int next = node[target].next;

		node[prev].next = next;
		node[next].prev = prev;
	}
};

MY_LIST my_list;
list<int> stl_list;

int main()
{
	// make test case..
	int cur_size = 0;
	for (int i = 0; i < NODE_SIZE; ++i) {
		if (i < NODE_SIZE / 3) {
			test_cmd[i][0] = rand() % 2;
		}
		else {
			test_cmd[i][0] = rand() % 6;
		}

		switch (test_cmd[i][0]) {
		case PUSH_BACK:
		case PUSH_FRONT: {
			test_cmd[i][1] = rand();
			++cur_size;
			break;
		}
		case INSERT: {
			test_cmd[i][1] = rand() % cur_size;
			test_cmd[i][2] = rand();
			++cur_size;
			break;
		}
		case POP_BACK:
		case POP_FRONT: {
			--cur_size;
			break;
		}
		case ERASE: {
			test_cmd[i][1] = rand() % cur_size;
			--cur_size;
			break;
		}
		}
	}

	// test my list
	int my_list_begin = GetTickCount();
	for (int i = 0; i < NODE_SIZE; ++i) {
		switch (test_cmd[i][0]) {
		case PUSH_BACK: {
			my_list.push_back(test_cmd[i][1]);
			break;
		}
		case PUSH_FRONT: {
			my_list.push_front(test_cmd[i][1]);
			break;
		}
		case INSERT: {
			my_list.insert(test_cmd[i][1], test_cmd[i][2]);
			break;
		}

		case POP_BACK: {
			my_list.pop_back();
			break;
		}
		case POP_FRONT: {
			my_list.pop_front();
			break;
		}
		case ERASE: {
			my_list.erase(test_cmd[i][1]);
			break;
		}
		}
	}
	int my_list_end = GetTickCount();

	// test stl list
	int stl_list_begin = GetTickCount();
	for (int i = 0; i < NODE_SIZE; ++i) {
		switch (test_cmd[i][0]) {
		case PUSH_BACK: {
			stl_list.push_back(test_cmd[i][1]);
			break;
		}
		case PUSH_FRONT: {
			stl_list.push_front(test_cmd[i][1]);
			break;
		}
		case INSERT: {
			list<int>::iterator it = stl_list.begin();
			for (int k = 0; k < test_cmd[i][1]; ++k) {
				++it;
			}
			stl_list.insert(it, test_cmd[i][2]);
			break;
		}

		case POP_BACK: {
			stl_list.pop_back();
			break;
		}
		case POP_FRONT: {
			stl_list.pop_front();
			break;
		}
		case ERASE: {
			list<int>::iterator it = stl_list.begin();
			for (int k = 0; k < test_cmd[i][1]; ++k) {
				++it;
			}
			stl_list.erase(it);
			break;
		}
		}
	}
	int stl_list_end = GetTickCount();

	//time compare
	printf("my list : %d\n", (my_list_end - my_list_begin));
	printf("stl list : %d\n", (stl_list_end - stl_list_begin));

	//result test
	list<int>::iterator it = stl_list.begin();
	int cur = my_list.node[my_list.HEAD].next;
	while (it != stl_list.end()) {
		if (*it != my_list.node[cur].val) {
			printf("Error\n");
		}
		++it;
		cur = my_list.node[cur].next;
	}

	return 0;
}


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Merge Sort

Data Structure 2019. 2. 10. 23:43



#include <stdio.h>
#include "Windows.h"
#include <algorithm>
using namespace std;

const int MAX_SIZE = 500000;

int arr_size;
int ms[MAX_SIZE], qs[MAX_SIZE], stls[MAX_SIZE], buf[MAX_SIZE];

void merge_sort(int* p, int len) {
	if (len < 2)	return;
	int i, j, k, mid;
	mid = (len / 2);
	i = 0, j = mid, k = 0;

	merge_sort(p, mid);
	merge_sort((p + mid), (len - mid));

	while (i < mid && j < len) {
		if (p[i] < p[j]) {
			buf[k++] = p[i++];
		}
		else {
			buf[k++] = p[j++];
		}
	}

	while (i < mid) {
		buf[k++] = p[i++];
	}

	while (j < len) {
		buf[k++] = p[j++];
	}

	for (int i = 0; i < len; ++i) {
		p[i] = buf[i];
	}
}

void qsort(int* p, int left, int right) {
	if (left >= right)	return;
	int l = left - 1;
	int r = right + 1;
	int mid = p[(l + r) / 2];
	while (1) {
		while (p[++l] < mid);
		while (p[--r] > mid);
		if (l >= r)	break;
		int temp = p[l];
		p[l] = p[r];
		p[r] = temp;
	}
	qsort(p, left, l - 1);
	qsort(p, r + 1, right);
}


int main()
{
	arr_size = MAX_SIZE;

	for (int i = 0; i < arr_size; ++i) {
		ms[i] = rand();
		qs[i] = stls[i] = ms[i];
	}

	int quick_sort_begin = GetTickCount();
	qsort(qs, 0, arr_size - 1);
	int quick_sort_end = GetTickCount();

	int merge_sort_begin = GetTickCount();
	merge_sort(ms, arr_size);
	int merge_sort_end = GetTickCount();

	int stl_sort_begin = GetTickCount();
	sort(stls, stls + arr_size);
	int stl_sort_end = GetTickCount();

	printf("my quick sort : %d\n", (quick_sort_end - quick_sort_begin));
	printf("my merge sort : %d\n", (merge_sort_end - merge_sort_begin));
	printf("stl sort : %d\n", (stl_sort_end - stl_sort_begin));
	printf("=====================================\n");

	quick_sort_begin = GetTickCount();
	qsort(qs, 0, arr_size - 1);
	quick_sort_end = GetTickCount();

	merge_sort_begin = GetTickCount();
	merge_sort(ms, arr_size);
	merge_sort_end = GetTickCount();

	stl_sort_begin = GetTickCount();
	sort(stls, stls + arr_size);
	stl_sort_end = GetTickCount();

	printf("my quick sort : %d\n", (quick_sort_end - quick_sort_begin));
	printf("my merge sort : %d\n", (merge_sort_end - merge_sort_begin));
	printf("stl sort : %d\n", (stl_sort_end - stl_sort_begin));
	printf("=====================================\n");

	for (int i = 0; i < arr_size; ++i) {
		if (qs[i] != stls[i] || ms[i] != stls[i]) {
			printf("Error\n");
		}
	}

	return 0;
}


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