LeetCode 2016 400,398,397,396,393,352,284

来源：互联网发布：js then的用法编辑：程序博客网时间：2024/04/29 21:34

400 Nth Digit

class Solution {public:    vector<long long> f;    vector<long long> g;    vector<long long> tens;    int dUpper = 10;    int th = 9;    void countNumbers()    {        long long ten = 1;        long long nines = 9;        g.clear();g.resize(11);g[0]=0;        f.clear();f.resize(11);f[0]=0;        tens.clear();tens.resize(11);tens[0]=0;        for(long long i=1;i<=dUpper;i++)        {            f[i]=0;            f[i]=(nines - ten + 1)*i;            g[i]=g[i-1]+f[i];            tens[i]=ten;            ten*=10;            nines = nines * 10 + 9;        }        tens[1]=0;    }    int findGreatIndex(int n)    {        int i;        for(i=1;i<=dUpper;i++)        {            if (g[i]>=n) break;        }        return i;    }    int findDigit(int st, int n)    {        int i=st-1,cnt=0,len;        string s;        for(;;)        {            i++;            stringstream strStream;            strStream << i;            s = strStream.str();            len = s.size();            cnt+=len;            if (cnt>=n)            {                cnt-=len;                break;            }        }        cnt=n-cnt;        return s[cnt-1]-'0';    }    int findNthDigit(int n)    {        if (n<=9) return findDigit(1,n);        countNumbers();        int index = findGreatIndex(n);        n -=g[index-1];        int d = n/index;        n-= d*index;        int st = tens[index]+d;        if (n==0)        {            return (st-1) % 10;        }        else        return findDigit(st,n);    }};

398 Random Pick Index

class Solution {public:    vector<int> numbers;    int len;    Solution(vector<int> nums)    {        this->numbers = nums;        this->len = nums.size();    }    int pick(int target)    {        int ans = 0;        while (numbers[ans]!=target) ans++;        int node = ans + 1;        int k=1;        int n=k+1;        while (node < len)        {            if (numbers[node]!=target)            {                node++;                continue;            }            int index=rand()%n;            if (index==0) ans=node;            n++;            node++;        }        return ans;    }};

397 Integer Replacement

class Solution {public:    int integerReplacement(int n)    {        int cnt = 0;        long long left = n;        while(left!=1)        {            //cout<<left<<endl;            while(left % 2 ==0 && left > 1)            {                cnt++;                left /=2;            }            if (left ==1) break;            long long minusTwo = 0,plusTwo = 0;            long long minusOne = left - 1, plusOne = left + 1;            while(minusOne%2==0)             {                minusOne/=2;                minusTwo++;            }            while(plusOne%2==0)             {                plusOne/=2;                plusTwo++;            }            if (minusOne ==1 && plusOne ==1 )             {                cnt += min(plusTwo,minusTwo)+1;                break;            }            if (minusTwo > plusTwo) left--; else left++;            cnt++;        }        return cnt;    }};

396 Rotate Function

class Solution {public:    int maxRotateFunction(vector<int>& A)    {        int ans = 0, tmpans = 0;        int len = A.size();        if (len ==0) return ans;        int sum = 0;        vector<int> nums;        nums.clear();        for(int i=0;i<2;i++)        {            for(int j=0;j<len;j++)                nums.push_back(A[j]);        }        for(int i=0;i<len;i++)        {            sum += A[i];            ans += A[i]*i;        }        int iUpper = len -1;        tmpans = ans;        for(int i=0;i<iUpper;i++)        {            tmpans -=sum;            tmpans += A[i]*len;            if (tmpans>ans) ans = tmpans;        }        return ans;    }};

393 UTF-8 Validation

class Solution {public:    int len;    vector< pair<int,int> > head;    vector< pair<int,int> > interval;    vector<int> lower;    vector<int> upper;    int upNums = 5;    void initial()    {        lower.clear();upper.clear();        // [0] ans the 10xx xxxx        // [1000 0000 , 1011 1111]        lower.push_back(128);upper.push_back(191);        // [0000 0000 , 0111 1111]        lower.push_back(0);upper.push_back(127);        // [1100 0000 , 1101 1111]        lower.push_back(192);upper.push_back(223);        // [1110 0000 , 1110 1111]        lower.push_back(224);upper.push_back(239);        // [1111 0000 , 1111 0111]        lower.push_back(240);upper.push_back(247);        head.clear();interval.clear();        return ;    }    bool validUtf8(vector<int>& data)    {        this->len = data.size();        initial();        int index = 0;        while(index<len)        {            if (lower[1]<=data[index] && data[index]<=upper[1])            {                index++;                continue;            }            bool headFlag = false;            int i;            for(i=2;i<=4;i++)            {                if (lower[i]<=data[index] && data[index]<=upper[i])                {                    headFlag = true;                    break;                }            }            //cout<<i<<endl;            if (!headFlag) return false;            int j;            for(j=index+1;j<index+i;j++)            {                //cout<<"j = "<<j<<endl;                if (data[j]>upper[0] || data[j]<lower[0]) return false;            }            index = j;        }        return true;    }};

352 Data Stream as Disjoint Intervals

class SummaryRanges {public:    /** Initialize your data structure here. */    set<int> s;    SummaryRanges()    {        s.clear();    }    void addNum(int val)    {        if (s.find(val)==s.end()) s.insert(val);    }    vector<Interval> getIntervals()    {        vector<int> nums;        vector<Interval> ans;        ans.clear();        nums.clear();        for(set<int>::iterator it = s.begin();it!=s.end();it++)            nums.push_back((*it));        if (nums.size()==0) return ans;        int left=0,right=0;        int len=nums.size();        nums.push_back(nums[len-1]-1);        len++;        for(int i=1;i<len;i++)        {            if (nums[i]==nums[i-1]+1)            {                right=i;                continue;            }            Interval tmp = Interval(nums[left],nums[right]);            ans.push_back(tmp);            left=i;right=i;        }        return ans;    }};

284 Peeking Iterator

// Below is the interface for Iterator, which is already defined for you.// **DO NOT** modify the interface for Iterator.class Iterator {    struct Data;Data* data;public:Iterator(const vector<int>& nums);Iterator(const Iterator& iter);virtual ~Iterator();// Returns the next element in the iteration.int next();// Returns true if the iteration has more elements.bool hasNext() const;};class PeekingIterator : public Iterator {public:PeekingIterator(const vector<int>& nums) : Iterator(nums) {    // Initialize any member here.    // **DO NOT** save a copy of nums and manipulate it directly.    // You should only use the Iterator interface methods.    }    // Returns the next element in the iteration without advancing the iterator.int peek() {    return Iterator(*this).next();}// hasNext() and next() should behave the same as in the Iterator interface.// Override them if needed.int next() {    return Iterator::next();}bool hasNext() const {    return Iterator::hasNext();}};

0 0