31 lines
1.4 KiB
C++
31 lines
1.4 KiB
C++
#include <vector>
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#include <algorithm>
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#include <iostream>
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/**
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* 452. Minimum Number of Arrows to Burst Balloons
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* There are some spherical balloons taped onto a flat wall that represents the XY-plane. The balloons are represented as a 2D integer array points where points[i] = [xstart, xend] denotes a balloon whose horizontal diameter stretches between xstart and xend. You do not know the exact y-coordinates of the balloons.
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* Arrows can be shot up directly vertically (in the positive y-direction) from different points along the x-axis. A balloon with xstart and xend is burst by an arrow shot at x if xstart <= x <= xend. There is no limit to the number of arrows that can be shot. A shot arrow keeps traveling up infinitely, bursting any balloons in its path.
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* Given the array points, return the minimum number of arrows that must be shot to burst all balloons.
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*/
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class Solution {
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public:
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static int findMinArrowShots(std::vector<std::vector<int>>& points) {
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std::sort(points.begin(), points.end(), [](const std::vector<int>& l, const std::vector<int>& r) { return l[1] < r[1]; });
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int ret = 0, n = points.size();
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for (int i = 0, r; i < n;) {
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++ret;
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r = points[i][1];
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while (i < n && points[i][0] <= r)
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++i;
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}
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return ret;
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}
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};
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int main() {
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std::vector<std::vector<int>> v {{3,9},{7,12},{3,8},{6,8},{9,10},{2,9},{0,9},{3,9},{0,6},{2,8}}; // {{10, 16}, {2, 8}, {1, 6}, {7, 12}};
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std::cout << Solution::findMinArrowShots(v);
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return 0;
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} |