{

int size = (int)nums.size();

if (size == 1) return 0;

std::vector<int> steps(size, 0); //steps[i]表示到达i所需要的最少步数

int maxReachableIdx = 0;

for (int i = 0; i <= maxReachableIdx && i < size; ++i) {

// 从当前位置i能到达更远位置或者能到达终点时，就要尝试更新steps

if (maxReachableIdx < nums[i] + i || nums[i] + i >= size - 1) {

maxReachableIdx = nums[i] + i;

for (int j = i + 1; j <= maxReachableIdx && j < size; ++j) {

if (steps[j] == 0) {

steps[j] = steps[i] + 1;

} else {

steps[j] = std::min(steps[i] + 1, steps[j]);

}

}

}

}

return steps[size - 1];