PART4 前缀和
找到最高海拔
lc.1732
class Solution {
public:
int largestAltitude(vector& gain) {
int maxAltitude = 0, currAltitude = 0;
for (int delta : gain) {
currAltitude += delta;
maxAltitude = max(maxAltitude, currAltitude);
}
return maxAltitude;
}
}; 寻找数组的中心下标
lc.724
class Solution {
public:
int pivotIndex(vector& nums) {
if (nums.size() == 1) {
return 0;
}
int sumRight = 0, sumLeft = 0;
for (int i = 1; i < nums.size(); i++) {
sumRight += nums[i];
}
int curr = 0;
while (curr < nums.size() - 1) {
if (sumLeft == sumRight) {
return curr;
}
sumLeft += nums[curr];
sumRight -= nums[curr + 1];
curr++;
}
return sumLeft == 0 ? curr : -1;
}
}; 
