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JumpGame.cpp
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JumpGame.cpp
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class JumpGame {
public:
// 1. dp
int jump_dp(vector<int>& nums) {
vector<int> dp(nums.size());
dp[dp.size() - 1] = 0;
for (int i = num.size() - 2; i >= 0; --i) {
int maxStep = min(i + nums[i], (int)nums.size() - 1);
dp[i] = INT_MAX;
for (int j = i + 1; j <= maxStep; ++j) {
if (dp[i] != INT_MAX) {
dp[i] = min(dp[i], dp[j] + 1);
}
}
}
return dp[0];
}
// 2. bfs
int jump_bfs(vector<int>& nums) {
if (nums.size() == 0)
return INT_MAX;
if (nums.size() == 1)
return 0;
queue<int> queue;
vector<bool> visited(nums.size());
queue.push(0);
visited[0] = true;
int steps = 0;
while (!queue.empty()) {
int size = queue.size();
for (int i = 0; i < size; ++i) {
int cur_index = queue.front();
queue.pop();
for (int j = min(cur_index + nums[cur_index], (int)nums.size() - 1); j >= cur_index; --j) {
if (j == nums.size() - 1)
return steps + 1;
if (!visited[j]) {
queue.push(j);
visited[j] = true;
}
}
}
++steps;
}
return INT_MAX;
}
};