LeetCode-455. Assign Cookies

Description

Assume you are an awesome parent and want to give your children some cookies. But, you should give
each child at most one cookie. Each child i has a greed factor gi, which is the minimum size of a
cookie that the child will be content with; and each cookie j has a size sj. If sj >= gi, we can
assign the cookie j to the child i, and the child i will be content. Your goal is to maximize the
number of your content children and output the maximum number.

Note

You may assume the greed factor is always positive.
You cannot assign more than one cookie to one child.

Example 1

Input: [1,2,3], [1,1]

Output: 1

Explanation: You have 3 children and 2 cookies. The greed factors of 3 children are 1, 2, 3.
And even though you have 2 cookies, since their size is both 1, you could only make the child whose greed factor is 1 content.
You need to output 1.

Example 2

Input: [1,2], [1,2,3]

Output: 2

Explanation: You have 2 children and 3 cookies. The greed factors of 2 children are 1, 2.
You have 3 cookies and their sizes are big enough to gratify all of the children,
You need to output 2.

Solution 1(C++)

class Solution {
public:
int findContentChildren(vector<int>& g, vector<int>& s) {
sort(g.begin(), g.end());
sort(s.begin(), s.end());
int num=0;
for(int i=0, j=0; i<g.size() && j<s.size(); j++){
if(g[i]<s[j] || g[i]==s[j]){num++; i++;}
}
return num;
}
};

Solution 2(C++)

static int x = []() { std::ios::sync_with_stdio(false); cin.tie(NULL); return 0; }();
class Solution {
int findge(int*nums, int v, int s, int e) const {
while (s < e) {
int m = s + ((e - s) >> 1), vv = nums[m];
if (vv >= v) { e = m; }
else { s = m + 1; }
}
return s == e && nums[s] >= v ? s : INT_MAX;
};
public:
int findContentChildren(vector<int>& g, vector<int>& s) const {
int ns = (int)s.size();
if (ns --) {
int nc = (int)g.size();
if (nc) {
int index = 0, count = 0, *ps = &s[0], *pg = &g[0], *pge = pg + nc;
std::sort(g.begin(), g.end());
std::sort(s.begin(), s.end());
while (pg < pge) {
index = findge(ps, *pg++, index, ns);
if (index == INT_MAX) { return count; }
++index;
++count;
}
return count;
}
}
return 0;
};
};

Solution 3(C++)

class Solution {
public:
int findContentChildren(vector<int>& g, vector<int>& s) {
priority_queue<int> gPq;
priority_queue<int> sPq;

for(int& gi : g) {
gPq.push(gi);
}

for(int& si : s) {
sPq.push(si);
}

int matched = 0;
while(gPq.size() > 0 && sPq.size() > 0) {

if(gPq.top() > sPq.top()) {
gPq.pop();
continue; // cannot satisfy this kid
} else { //(gPq.top() <= sPq.top())
++matched;
sPq.pop();
gPq.pop();
}
}
return matched;
}
};

算法分析

程序分析