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BinarySearch.cpp
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252 lines (226 loc) · 4.81 KB
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#include "BinarySearch.h"
int Solution::BinarySearchValue(std::vector<int> &Array, int nlow, int nHeigth, int nValue)
{
if (nlow >= nHeigth)
return INT_MIN;
int nMedian = nlow + (nHeigth - nlow) / 2;
if (Array[nMedian] = nValue)
{
return nMedian;
}
else if (Array[nMedian] > nValue)
{
return BinarySearchValue(Array, nlow, nMedian - 1, nValue);
}
else
return BinarySearchValue(Array, nMedian + 1, nHeigth, nValue);
}
int Solution::BinarySearchValueFirst(std::vector<int>Array, int nvalue)
{
int min = 0, max = Array.size();
int mid = 0;
while (min <= max)
{
mid = (max + min) / 2;
if (nvalue > Array[mid])
{
min = mid + 1;
}
else
{
max = mid;
}
if (max == min)
{
break;
}
}
if (Array[min] != nvalue)
{//当查找元素不存在时，返回-1
return -1;
}
else
{
return min;
}
}
int Solution::BinarySearchValueLast(std::vector<int>Array, int nvalue)
{
int min = 0, max = Array.size() - 1;
int mid = 0;
while (min <= max)
{
mid = (max + min + 1) / 2;
if (nvalue >= Array[mid])
{
min = mid;
}
else
{
max = mid - 1;
}
if (max == min)
{
break;
}
}
if (Array[max] != nvalue)
{//当查找元素不存在时，返回-1
return -1;
}
else
{
return max;
}
}
void Solution::TestSearch()
{
std::vector<int> listArray;
listArray.push_back(1);
listArray.push_back(1);
listArray.push_back(3);
listArray.push_back(3);
listArray.push_back(5);
listArray.push_back(5);
BinarySearchValueFirst(listArray, 3);
}
/*
查找第一个与key相等的元素，也就是说等于查找key值的元素有很多，返回这些元素最左边的元素的下标。
*/
int Solution::BinarySearchLeft(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
while ( nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] >= nval)
nRight = nMid - 1;
else
nLeft = nMid - 1;
}
if (nLeft < Array.size() - 1 && Array[nLeft] == nval)
{
return nLeft;
}
return -1;
}
/*
查找最后一个与key相等的元素，也就是等于查找key值的元素有好多个，返回这些元素最右边元素的下标。
*/
int Solution::BinarySearchRigth(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
while (nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] > nval)
nRight = nMid - 1;
else
nLeft = nMid + 1;
}
if (nRight < Array.size() && Array[nRight] == nval)
return nLeft;
return -1;
}
/*
//找第一个等于或者大于key的元素，查找第一个等于或者大于key的元素，也就是说查找key值的元素有好多个，
//返回这些元素最左边元素的下标；如果没有等于key值的元素，则返回大于key的最左边元素的下标。
*/
int Solution::BinarySearchHightBound(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
if (Array[nRight] < nval)
return -1;
while (nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] >= nval)
nRight = nMid - 1;
else
nLeft = nMid + 1;
}
return nLeft;
}
/*
查找第一个大于key的元素。查找第一个大于key的值，也就是说返回大于key的最左边元素的下标
*/
int Solution::BinarySearchfirstGreatVal(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
if (Array[nRight] < nval)
return -1;
while (nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] >= nval)
nLeft = nMid - 1;
else
nRight = nMid + 1;
}
return nLeft;
}
/*查找最后一个等于或者小于key的元素。查找最后一个等于或者小于key的元素，
也就是说等于查找key值有很多，返回这些元素最右边的元素的下标；如果没有等于key值的元素，则返回小于key值的最右边元素的下标。*/
int Solution::BinarySearchLastLessAEqulVal(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
if (Array[nLeft] > nval)
return -1;
while (nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] > nval)
nRight = nMid - 1;
else
nLeft = nMid + 1;
}
return nRight;
}
//查找最后一个小于Key 的值
int Solution::BinarySearchLastLessVal(std::vector<int>Array, int nval)
{
int nLeft = 0;
int nRight = Array.size() - 1;
if (Array[nLeft] >= nval)
return -1;
while (nLeft <= nRight)
{
int nMid = nLeft + (nRight - nLeft) / 2;
if (Array[nMid] >= nval)
nRight = nMid - 1;
else
nLeft = nMid + 1;
}
return nRight;
}
void Solution::TestLowerBound()
{
Solution solu;
std::vector<int> listArray;
listArray.push_back(1);
listArray.push_back(1);
listArray.push_back(3);
listArray.push_back(3);
listArray.push_back(5);
listArray.push_back(5);
int nLowBound = solu.BinarySerchLowerBound(listArray, 0, listArray.size() - 1, 3);
cout << nLowBound << endl;
}
int Solution::BinarySerchLowerBound(std::vector<int>&Array, int nlow, int nHeight, int nValue)
{
if (nlow >= nHeight)
{
return -1;
}
int nMedian = nlow + (nHeight - nlow) / 2;
if (Array[nMedian] >= nValue)
nHeight = nMedian - 1;
else
nlow = nMedian + 1;
return BinarySerchLowerBound(Array, nlow, nHeight, nValue);
}