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| public class ClimbingStairs {
public int climbStairs1(int n) {
assert n > 0;
if (n == 1) {
return 1;
}
if (n == 2) {
return 2;
}
return climbStairs1(n - 1) + climbStairs1(n - 2);
}
public int climbStairs2(int n) {
assert n > 0;
if (n == 1) {
return 1;
}
if (n == 2) {
return 2;
}
int x = 1;
int y = 2;
int result = 0;
for (int i = 3; i <= n; i++) {
result = x + y;
x = y;
y = result;
}
return result;
}
}
|