题目:2234. 花园的最大总美丽值 - 力扣(LeetCode)
1. 先对flowers进行升序排序,计算现有“完善花园”的数量minFull;如果没有,minFull为n。
2. 计算前缀和f[]。
3. 从i=(minFull-1 to 0)枚举从第i个开始的花园都变成“完善花园”后剩余的花的数量,计算剩余的花可以使最小值最大的值
4. 因为我们是倒序枚举的,设“非完善花园”的最小数量是flowers[j],则j在美剧过程中一定不会增长,可以通过f[]和剩余的花的数量快速计算出是否可以满足“非完善花园”的最小数量是flowers[j]这一条件;如果满足该条件后花朵数量还有剩余,可以计算可以给所有“非完善花园”各增加多少朵花
O(nlog(n))的排序+O(n)的遍历就可以得到答案了:
class Solution {
public:
long long maximumBeauty(vector<int>& flowers, long long newFlowers, int target1, int full1, int partial1) {
long long target = target1;
long long full = full1;
long long partial = partial1;
sort(flowers.begin(), flowers.end());
long long n = flowers.size();
long long* f = new long long[n];
if (flowers[0] >= target) {
return full * n;
}
f[0] = flowers[0];
long long minFull = n;
for (int i = 1; i < n; i++) {
f[i] = flowers[i];
f[i] += f[i - 1];
if (flowers[i] >= target) {
minFull = i;
break;
}
}
long long ret = 0;
long long j = minFull - 1;
long long flowerJ = flowers[j];
long long score, remain, temp;
for (long long i = minFull - 1; i >= 0; i--) {
if (j > i) {
j = i;
flowerJ = flowers[j];
}
while (j >= 0 && f[j] + newFlowers < flowerJ * (j + 1)) {
j--;
flowerJ = flowers[j];
}
remain = newFlowers - (flowerJ * (j + 1) - f[j]);
temp = flowerJ + remain / (j + 1);
if (temp >= target) {
temp = target - 1;
}
score = (n - 1 - i) * full + temp * partial;
if (score > ret) {
ret = score;
}
newFlowers -= (target - flowers[i]);
if (newFlowers < 0) {
break;
}
}
if (newFlowers >= 0) {
score = n * full;
if (score > ret) {
ret = score;
}
}
return ret;
}
};