Minimum number of Jumps
Mathematica, 197 193 chars
Brute force.
Min[Length/@Select[Join[{1},#,{n},Reverse@#2]&amp;@@@Tuples[Subsets@Range[3,n=Length[i=FromDigits/@StringSplit@InputString[]]]-1,2],{}⋃#==Sort@#∧And@@Thread[i[[#]]≥Abs[#-Rest@#~Append~1]]&amp;]]/.∞-&gt;-1